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[PATCH v10 6/7] Row pattern recognition patch (tests). 687+ messages / 2 participants [nested] [flat]
* [PATCH v10 6/7] Row pattern recognition patch (tests). @ 2023-10-22 02:22 Tatsuo Ishii <ishii@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Tatsuo Ishii @ 2023-10-22 02:22 UTC (permalink / raw) --- src/test/regress/expected/rpr.out | 709 +++++++++++++++++++++++++++++ src/test/regress/parallel_schedule | 2 +- src/test/regress/sql/rpr.sql | 338 ++++++++++++++ 3 files changed, 1048 insertions(+), 1 deletion(-) create mode 100644 src/test/regress/expected/rpr.out create mode 100644 src/test/regress/sql/rpr.sql diff --git a/src/test/regress/expected/rpr.out b/src/test/regress/expected/rpr.out new file mode 100644 index 0000000000..8f8254d3b2 --- /dev/null +++ b/src/test/regress/expected/rpr.out @@ -0,0 +1,709 @@ +-- +-- Test for row pattern definition clause +-- +CREATE TEMP TABLE stock ( + company TEXT, + tdate DATE, + price INTEGER +); +INSERT INTO stock VALUES ('company1', '2023-07-01', 100); +INSERT INTO stock VALUES ('company1', '2023-07-02', 200); +INSERT INTO stock VALUES ('company1', '2023-07-03', 150); +INSERT INTO stock VALUES ('company1', '2023-07-04', 140); +INSERT INTO stock VALUES ('company1', '2023-07-05', 150); +INSERT INTO stock VALUES ('company1', '2023-07-06', 90); +INSERT INTO stock VALUES ('company1', '2023-07-07', 110); +INSERT INTO stock VALUES ('company1', '2023-07-08', 130); +INSERT INTO stock VALUES ('company1', '2023-07-09', 120); +INSERT INTO stock VALUES ('company1', '2023-07-10', 130); +INSERT INTO stock VALUES ('company2', '2023-07-01', 50); +INSERT INTO stock VALUES ('company2', '2023-07-02', 2000); +INSERT INTO stock VALUES ('company2', '2023-07-03', 1500); +INSERT INTO stock VALUES ('company2', '2023-07-04', 1400); +INSERT INTO stock VALUES ('company2', '2023-07-05', 1500); +INSERT INTO stock VALUES ('company2', '2023-07-06', 60); +INSERT INTO stock VALUES ('company2', '2023-07-07', 1100); +INSERT INTO stock VALUES ('company2', '2023-07-08', 1300); +INSERT INTO stock VALUES ('company2', '2023-07-09', 1200); +INSERT INTO stock VALUES ('company2', '2023-07-10', 1300); +SELECT * FROM stock; + company | tdate | price +----------+------------+------- + company1 | 07-01-2023 | 100 + company1 | 07-02-2023 | 200 + company1 | 07-03-2023 | 150 + company1 | 07-04-2023 | 140 + company1 | 07-05-2023 | 150 + company1 | 07-06-2023 | 90 + company1 | 07-07-2023 | 110 + company1 | 07-08-2023 | 130 + company1 | 07-09-2023 | 120 + company1 | 07-10-2023 | 130 + company2 | 07-01-2023 | 50 + company2 | 07-02-2023 | 2000 + company2 | 07-03-2023 | 1500 + company2 | 07-04-2023 | 1400 + company2 | 07-05-2023 | 1500 + company2 | 07-06-2023 | 60 + company2 | 07-07-2023 | 1100 + company2 | 07-08-2023 | 1300 + company2 | 07-09-2023 | 1200 + company2 | 07-10-2023 | 1300 +(20 rows) + +-- basic test using PREV +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | nth_second +----------+------------+-------+-------------+------------+------------ + company1 | 07-01-2023 | 100 | 100 | 140 | 07-02-2023 + company1 | 07-02-2023 | 200 | | | + company1 | 07-03-2023 | 150 | | | + company1 | 07-04-2023 | 140 | | | + company1 | 07-05-2023 | 150 | | | + company1 | 07-06-2023 | 90 | 90 | 120 | 07-07-2023 + company1 | 07-07-2023 | 110 | | | + company1 | 07-08-2023 | 130 | | | + company1 | 07-09-2023 | 120 | | | + company1 | 07-10-2023 | 130 | | | + company2 | 07-01-2023 | 50 | 50 | 1400 | 07-02-2023 + company2 | 07-02-2023 | 2000 | | | + company2 | 07-03-2023 | 1500 | | | + company2 | 07-04-2023 | 1400 | | | + company2 | 07-05-2023 | 1500 | | | + company2 | 07-06-2023 | 60 | 60 | 1200 | 07-07-2023 + company2 | 07-07-2023 | 1100 | | | + company2 | 07-08-2023 | 1300 | | | + company2 | 07-09-2023 | 1200 | | | + company2 | 07-10-2023 | 1300 | | | +(20 rows) + +-- basic test using PREV. UP appears twice +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+ UP+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | nth_second +----------+------------+-------+-------------+------------+------------ + company1 | 07-01-2023 | 100 | 100 | 150 | 07-02-2023 + company1 | 07-02-2023 | 200 | | | + company1 | 07-03-2023 | 150 | | | + company1 | 07-04-2023 | 140 | | | + company1 | 07-05-2023 | 150 | | | + company1 | 07-06-2023 | 90 | 90 | 130 | 07-07-2023 + company1 | 07-07-2023 | 110 | | | + company1 | 07-08-2023 | 130 | | | + company1 | 07-09-2023 | 120 | | | + company1 | 07-10-2023 | 130 | | | + company2 | 07-01-2023 | 50 | 50 | 1500 | 07-02-2023 + company2 | 07-02-2023 | 2000 | | | + company2 | 07-03-2023 | 1500 | | | + company2 | 07-04-2023 | 1400 | | | + company2 | 07-05-2023 | 1500 | | | + company2 | 07-06-2023 | 60 | 60 | 1300 | 07-07-2023 + company2 | 07-07-2023 | 1100 | | | + company2 | 07-08-2023 | 1300 | | | + company2 | 07-09-2023 | 1200 | | | + company2 | 07-10-2023 | 1300 | | | +(20 rows) + +-- basic test using PREV. Use '*' +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP* DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | nth_second +----------+------------+-------+-------------+------------+------------ + company1 | 07-01-2023 | 100 | 100 | 140 | 07-02-2023 + company1 | 07-02-2023 | 200 | | | + company1 | 07-03-2023 | 150 | | | + company1 | 07-04-2023 | 140 | | | + company1 | 07-05-2023 | 150 | 150 | 90 | 07-06-2023 + company1 | 07-06-2023 | 90 | | | + company1 | 07-07-2023 | 110 | 110 | 120 | 07-08-2023 + company1 | 07-08-2023 | 130 | | | + company1 | 07-09-2023 | 120 | | | + company1 | 07-10-2023 | 130 | | | + company2 | 07-01-2023 | 50 | 50 | 1400 | 07-02-2023 + company2 | 07-02-2023 | 2000 | | | + company2 | 07-03-2023 | 1500 | | | + company2 | 07-04-2023 | 1400 | | | + company2 | 07-05-2023 | 1500 | 1500 | 60 | 07-06-2023 + company2 | 07-06-2023 | 60 | | | + company2 | 07-07-2023 | 1100 | 1100 | 1200 | 07-08-2023 + company2 | 07-08-2023 | 1300 | | | + company2 | 07-09-2023 | 1200 | | | + company2 | 07-10-2023 | 1300 | | | +(20 rows) + +-- last_value() should remain consistent +SELECT company, tdate, price, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | last_value +----------+------------+-------+------------ + company1 | 07-01-2023 | 100 | 140 + company1 | 07-02-2023 | 200 | + company1 | 07-03-2023 | 150 | + company1 | 07-04-2023 | 140 | + company1 | 07-05-2023 | 150 | + company1 | 07-06-2023 | 90 | 120 + company1 | 07-07-2023 | 110 | + company1 | 07-08-2023 | 130 | + company1 | 07-09-2023 | 120 | + company1 | 07-10-2023 | 130 | + company2 | 07-01-2023 | 50 | 1400 + company2 | 07-02-2023 | 2000 | + company2 | 07-03-2023 | 1500 | + company2 | 07-04-2023 | 1400 | + company2 | 07-05-2023 | 1500 | + company2 | 07-06-2023 | 60 | 1200 + company2 | 07-07-2023 | 1100 | + company2 | 07-08-2023 | 1300 | + company2 | 07-09-2023 | 1200 | + company2 | 07-10-2023 | 1300 | +(20 rows) + +-- omit "START" in DEFINE but it is ok because "START AS TRUE" is +-- implicitly defined. per spec. +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | nth_second +----------+------------+-------+-------------+------------+------------ + company1 | 07-01-2023 | 100 | 100 | 140 | 07-02-2023 + company1 | 07-02-2023 | 200 | | | + company1 | 07-03-2023 | 150 | | | + company1 | 07-04-2023 | 140 | | | + company1 | 07-05-2023 | 150 | | | + company1 | 07-06-2023 | 90 | 90 | 120 | 07-07-2023 + company1 | 07-07-2023 | 110 | | | + company1 | 07-08-2023 | 130 | | | + company1 | 07-09-2023 | 120 | | | + company1 | 07-10-2023 | 130 | | | + company2 | 07-01-2023 | 50 | 50 | 1400 | 07-02-2023 + company2 | 07-02-2023 | 2000 | | | + company2 | 07-03-2023 | 1500 | | | + company2 | 07-04-2023 | 1400 | | | + company2 | 07-05-2023 | 1500 | | | + company2 | 07-06-2023 | 60 | 60 | 1200 | 07-07-2023 + company2 | 07-07-2023 | 1100 | | | + company2 | 07-08-2023 | 1300 | | | + company2 | 07-09-2023 | 1200 | | | + company2 | 07-10-2023 | 1300 | | | +(20 rows) + +-- the first row start with less than or equal to 100 +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (LOWPRICE UP+ DOWN+) + DEFINE + LOWPRICE AS price <= 100, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | 100 | 140 + company1 | 07-02-2023 | 200 | | + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | | + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | 90 | 120 + company1 | 07-07-2023 | 110 | | + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | 50 | 1400 + company2 | 07-02-2023 | 2000 | | + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | | + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | 60 | 1200 + company2 | 07-07-2023 | 1100 | | + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- second row raises 120% +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (LOWPRICE UP+ DOWN+) + DEFINE + LOWPRICE AS price <= 100, + UP AS price > PREV(price) * 1.2, + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | 100 | 140 + company1 | 07-02-2023 | 200 | | + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | | + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | | + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | 50 | 1400 + company2 | 07-02-2023 | 2000 | | + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | | + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | | + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- using NEXT +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UPDOWN) + DEFINE + START AS TRUE, + UPDOWN AS price > PREV(price) AND price > NEXT(price) +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | 100 | 200 + company1 | 07-02-2023 | 200 | | + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | 140 | 150 + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | 110 | 130 + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | 50 | 2000 + company2 | 07-02-2023 | 2000 | | + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | 1400 | 1500 + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | 1100 | 1300 + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + INITIAL + PATTERN (START UPDOWN) + DEFINE + START AS TRUE, + UPDOWN AS price > PREV(price) AND price > NEXT(price) +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | 100 | 200 + company1 | 07-02-2023 | 200 | | + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | 140 | 150 + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | 110 | 130 + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | 50 | 2000 + company2 | 07-02-2023 | 2000 | | + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | 1400 | 1500 + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | 1100 | 1300 + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- match everything +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + INITIAL + PATTERN (A+) + DEFINE + A AS TRUE +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | 100 | 130 + company1 | 07-02-2023 | 200 | | + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | | + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | | + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | 50 | 1300 + company2 | 07-02-2023 | 2000 | | + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | | + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | | + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- backtracking with reclassification of rows +-- using AFTER MATCH SKIP PAST LAST ROW +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + INITIAL + PATTERN (A+ B+) + DEFINE + A AS price > 100, + B AS price > 100 +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | | + company1 | 07-02-2023 | 200 | 07-02-2023 | 07-05-2023 + company1 | 07-03-2023 | 150 | | + company1 | 07-04-2023 | 140 | | + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | 07-07-2023 | 07-10-2023 + company1 | 07-08-2023 | 130 | | + company1 | 07-09-2023 | 120 | | + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | | + company2 | 07-02-2023 | 2000 | 07-02-2023 | 07-05-2023 + company2 | 07-03-2023 | 1500 | | + company2 | 07-04-2023 | 1400 | | + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | 07-07-2023 | 07-10-2023 + company2 | 07-08-2023 | 1300 | | + company2 | 07-09-2023 | 1200 | | + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- backtracking with reclassification of rows +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + INITIAL + PATTERN (A+ B+) + DEFINE + A AS price > 100, + B AS price > 100 +); + company | tdate | price | first_value | last_value +----------+------------+-------+-------------+------------ + company1 | 07-01-2023 | 100 | | + company1 | 07-02-2023 | 200 | 07-02-2023 | 07-05-2023 + company1 | 07-03-2023 | 150 | 07-03-2023 | 07-05-2023 + company1 | 07-04-2023 | 140 | 07-04-2023 | 07-05-2023 + company1 | 07-05-2023 | 150 | | + company1 | 07-06-2023 | 90 | | + company1 | 07-07-2023 | 110 | 07-07-2023 | 07-10-2023 + company1 | 07-08-2023 | 130 | 07-08-2023 | 07-10-2023 + company1 | 07-09-2023 | 120 | 07-09-2023 | 07-10-2023 + company1 | 07-10-2023 | 130 | | + company2 | 07-01-2023 | 50 | | + company2 | 07-02-2023 | 2000 | 07-02-2023 | 07-05-2023 + company2 | 07-03-2023 | 1500 | 07-03-2023 | 07-05-2023 + company2 | 07-04-2023 | 1400 | 07-04-2023 | 07-05-2023 + company2 | 07-05-2023 | 1500 | | + company2 | 07-06-2023 | 60 | | + company2 | 07-07-2023 | 1100 | 07-07-2023 | 07-10-2023 + company2 | 07-08-2023 | 1300 | 07-08-2023 | 07-10-2023 + company2 | 07-09-2023 | 1200 | 07-09-2023 | 07-10-2023 + company2 | 07-10-2023 | 1300 | | +(20 rows) + +-- ROWS BETWEEN CURRENT ROW AND offset FOLLOWING +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w, + count(*) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND 2 FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | count +----------+------------+-------+-------------+------------+------- + company1 | 07-01-2023 | 100 | 07-01-2023 | 07-03-2023 | 3 + company1 | 07-02-2023 | 200 | | | + company1 | 07-03-2023 | 150 | | | + company1 | 07-04-2023 | 140 | 07-04-2023 | 07-06-2023 | 3 + company1 | 07-05-2023 | 150 | | | + company1 | 07-06-2023 | 90 | | | + company1 | 07-07-2023 | 110 | 07-07-2023 | 07-09-2023 | 3 + company1 | 07-08-2023 | 130 | | | + company1 | 07-09-2023 | 120 | | | + company1 | 07-10-2023 | 130 | | | 0 + company2 | 07-01-2023 | 50 | 07-01-2023 | 07-03-2023 | 3 + company2 | 07-02-2023 | 2000 | | | + company2 | 07-03-2023 | 1500 | | | + company2 | 07-04-2023 | 1400 | 07-04-2023 | 07-06-2023 | 3 + company2 | 07-05-2023 | 1500 | | | + company2 | 07-06-2023 | 60 | | | + company2 | 07-07-2023 | 1100 | 07-07-2023 | 07-09-2023 | 3 + company2 | 07-08-2023 | 1300 | | | + company2 | 07-09-2023 | 1200 | | | + company2 | 07-10-2023 | 1300 | | | 0 +(20 rows) + +-- +-- Aggregates +-- +-- using AFTER MATCH SKIP PAST LAST ROW +SELECT company, tdate, price, + first_value(price) OVER w, + last_value(price) OVER w, + max(price) OVER w, + min(price) OVER w, + sum(price) OVER w, + avg(price) OVER w, + count(price) OVER w +FROM stock +WINDOW w AS ( +PARTITION BY company +ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING +AFTER MATCH SKIP PAST LAST ROW +INITIAL +PATTERN (START UP+ DOWN+) +DEFINE +START AS TRUE, +UP AS price > PREV(price), +DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | max | min | sum | avg | count +----------+------------+-------+-------------+------------+------+-----+------+-----------------------+------- + company1 | 07-01-2023 | 100 | 100 | 140 | 200 | 100 | 590 | 147.5000000000000000 | 4 + company1 | 07-02-2023 | 200 | | | | | | | + company1 | 07-03-2023 | 150 | | | | | | | + company1 | 07-04-2023 | 140 | | | | | | | + company1 | 07-05-2023 | 150 | | | | | | | 0 + company1 | 07-06-2023 | 90 | 90 | 120 | 130 | 90 | 450 | 112.5000000000000000 | 4 + company1 | 07-07-2023 | 110 | | | | | | | + company1 | 07-08-2023 | 130 | | | | | | | + company1 | 07-09-2023 | 120 | | | | | | | + company1 | 07-10-2023 | 130 | | | | | | | 0 + company2 | 07-01-2023 | 50 | 50 | 1400 | 2000 | 50 | 4950 | 1237.5000000000000000 | 4 + company2 | 07-02-2023 | 2000 | | | | | | | + company2 | 07-03-2023 | 1500 | | | | | | | + company2 | 07-04-2023 | 1400 | | | | | | | + company2 | 07-05-2023 | 1500 | | | | | | | 0 + company2 | 07-06-2023 | 60 | 60 | 1200 | 1300 | 60 | 3660 | 915.0000000000000000 | 4 + company2 | 07-07-2023 | 1100 | | | | | | | + company2 | 07-08-2023 | 1300 | | | | | | | + company2 | 07-09-2023 | 1200 | | | | | | | + company2 | 07-10-2023 | 1300 | | | | | | | 0 +(20 rows) + +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, + first_value(price) OVER w, + last_value(price) OVER w, + max(price) OVER w, + min(price) OVER w, + sum(price) OVER w, + avg(price) OVER w, + count(price) OVER w +FROM stock +WINDOW w AS ( +PARTITION BY company +ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING +AFTER MATCH SKIP TO NEXT ROW +INITIAL +PATTERN (START UP+ DOWN+) +DEFINE +START AS TRUE, +UP AS price > PREV(price), +DOWN AS price < PREV(price) +); + company | tdate | price | first_value | last_value | max | min | sum | avg | count +----------+------------+-------+-------------+------------+------+------+------+-----------------------+------- + company1 | 07-01-2023 | 100 | 100 | 140 | 200 | 100 | 590 | 147.5000000000000000 | 4 + company1 | 07-02-2023 | 200 | | | | | | | 0 + company1 | 07-03-2023 | 150 | | | | | | | 0 + company1 | 07-04-2023 | 140 | 140 | 90 | 150 | 90 | 380 | 126.6666666666666667 | 3 + company1 | 07-05-2023 | 150 | | | | | | | 0 + company1 | 07-06-2023 | 90 | 90 | 120 | 130 | 90 | 450 | 112.5000000000000000 | 4 + company1 | 07-07-2023 | 110 | 110 | 120 | 130 | 110 | 360 | 120.0000000000000000 | 3 + company1 | 07-08-2023 | 130 | | | | | | | 0 + company1 | 07-09-2023 | 120 | | | | | | | 0 + company1 | 07-10-2023 | 130 | | | | | | | 0 + company2 | 07-01-2023 | 50 | 50 | 1400 | 2000 | 50 | 4950 | 1237.5000000000000000 | 4 + company2 | 07-02-2023 | 2000 | | | | | | | 0 + company2 | 07-03-2023 | 1500 | | | | | | | 0 + company2 | 07-04-2023 | 1400 | 1400 | 60 | 1500 | 60 | 2960 | 986.6666666666666667 | 3 + company2 | 07-05-2023 | 1500 | | | | | | | 0 + company2 | 07-06-2023 | 60 | 60 | 1200 | 1300 | 60 | 3660 | 915.0000000000000000 | 4 + company2 | 07-07-2023 | 1100 | 1100 | 1200 | 1300 | 1100 | 3600 | 1200.0000000000000000 | 3 + company2 | 07-08-2023 | 1300 | | | | | | | 0 + company2 | 07-09-2023 | 1200 | | | | | | | 0 + company2 | 07-10-2023 | 1300 | | | | | | | 0 +(20 rows) + +-- +-- Error cases +-- +-- row pattern definition variable name must not appear more than once +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + ORDER BY tdate + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price), + UP AS price > PREV(price) +); +ERROR: syntax error at or near "ORDER" +LINE 6: ORDER BY tdate + ^ +-- pattern variable name must appear in DEFINE +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+ END) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); +ERROR: syntax error at or near "END" +LINE 8: PATTERN (START UP+ DOWN+ END) + ^ +-- FRAME must start at current row when row patttern recognition is used +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); +ERROR: FRAME must start at current row when row patttern recognition is used +-- SEEK is not supported +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + SEEK + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); +ERROR: SEEK is not supported +LINE 8: SEEK + ^ +HINT: Use INITIAL. diff --git a/src/test/regress/parallel_schedule b/src/test/regress/parallel_schedule index 4df9d8503b..896531002b 100644 --- a/src/test/regress/parallel_schedule +++ b/src/test/regress/parallel_schedule @@ -98,7 +98,7 @@ test: publication subscription # Another group of parallel tests # select_views depends on create_view # ---------- -test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps advisory_lock indirect_toast equivclass +test: select_views portals_p2 foreign_key cluster dependency guc bitmapops combocid tsearch tsdicts foreign_data window xmlmap functional_deps advisory_lock indirect_toast equivclass rpr # ---------- # Another group of parallel tests (JSON related) diff --git a/src/test/regress/sql/rpr.sql b/src/test/regress/sql/rpr.sql new file mode 100644 index 0000000000..38309652f9 --- /dev/null +++ b/src/test/regress/sql/rpr.sql @@ -0,0 +1,338 @@ +-- +-- Test for row pattern definition clause +-- + +CREATE TEMP TABLE stock ( + company TEXT, + tdate DATE, + price INTEGER +); +INSERT INTO stock VALUES ('company1', '2023-07-01', 100); +INSERT INTO stock VALUES ('company1', '2023-07-02', 200); +INSERT INTO stock VALUES ('company1', '2023-07-03', 150); +INSERT INTO stock VALUES ('company1', '2023-07-04', 140); +INSERT INTO stock VALUES ('company1', '2023-07-05', 150); +INSERT INTO stock VALUES ('company1', '2023-07-06', 90); +INSERT INTO stock VALUES ('company1', '2023-07-07', 110); +INSERT INTO stock VALUES ('company1', '2023-07-08', 130); +INSERT INTO stock VALUES ('company1', '2023-07-09', 120); +INSERT INTO stock VALUES ('company1', '2023-07-10', 130); +INSERT INTO stock VALUES ('company2', '2023-07-01', 50); +INSERT INTO stock VALUES ('company2', '2023-07-02', 2000); +INSERT INTO stock VALUES ('company2', '2023-07-03', 1500); +INSERT INTO stock VALUES ('company2', '2023-07-04', 1400); +INSERT INTO stock VALUES ('company2', '2023-07-05', 1500); +INSERT INTO stock VALUES ('company2', '2023-07-06', 60); +INSERT INTO stock VALUES ('company2', '2023-07-07', 1100); +INSERT INTO stock VALUES ('company2', '2023-07-08', 1300); +INSERT INTO stock VALUES ('company2', '2023-07-09', 1200); +INSERT INTO stock VALUES ('company2', '2023-07-10', 1300); + +SELECT * FROM stock; + +-- basic test using PREV +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- basic test using PREV. UP appears twice +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+ UP+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- basic test using PREV. Use '*' +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP* DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- last_value() should remain consistent +SELECT company, tdate, price, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- omit "START" in DEFINE but it is ok because "START AS TRUE" is +-- implicitly defined. per spec. +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w, + nth_value(tdate, 2) OVER w AS nth_second + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- the first row start with less than or equal to 100 +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (LOWPRICE UP+ DOWN+) + DEFINE + LOWPRICE AS price <= 100, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- second row raises 120% +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (LOWPRICE UP+ DOWN+) + DEFINE + LOWPRICE AS price <= 100, + UP AS price > PREV(price) * 1.2, + DOWN AS price < PREV(price) +); + +-- using NEXT +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UPDOWN) + DEFINE + START AS TRUE, + UPDOWN AS price > PREV(price) AND price > NEXT(price) +); + +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + INITIAL + PATTERN (START UPDOWN) + DEFINE + START AS TRUE, + UPDOWN AS price > PREV(price) AND price > NEXT(price) +); + +-- match everything + +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + INITIAL + PATTERN (A+) + DEFINE + A AS TRUE +); + +-- backtracking with reclassification of rows +-- using AFTER MATCH SKIP PAST LAST ROW +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + INITIAL + PATTERN (A+ B+) + DEFINE + A AS price > 100, + B AS price > 100 +); + +-- backtracking with reclassification of rows +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + INITIAL + PATTERN (A+ B+) + DEFINE + A AS price > 100, + B AS price > 100 +); + +-- ROWS BETWEEN CURRENT ROW AND offset FOLLOWING +SELECT company, tdate, price, first_value(tdate) OVER w, last_value(tdate) OVER w, + count(*) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND 2 FOLLOWING + AFTER MATCH SKIP PAST LAST ROW + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- +-- Aggregates +-- + +-- using AFTER MATCH SKIP PAST LAST ROW +SELECT company, tdate, price, + first_value(price) OVER w, + last_value(price) OVER w, + max(price) OVER w, + min(price) OVER w, + sum(price) OVER w, + avg(price) OVER w, + count(price) OVER w +FROM stock +WINDOW w AS ( +PARTITION BY company +ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING +AFTER MATCH SKIP PAST LAST ROW +INITIAL +PATTERN (START UP+ DOWN+) +DEFINE +START AS TRUE, +UP AS price > PREV(price), +DOWN AS price < PREV(price) +); + +-- using AFTER MATCH SKIP TO NEXT ROW +SELECT company, tdate, price, + first_value(price) OVER w, + last_value(price) OVER w, + max(price) OVER w, + min(price) OVER w, + sum(price) OVER w, + avg(price) OVER w, + count(price) OVER w +FROM stock +WINDOW w AS ( +PARTITION BY company +ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING +AFTER MATCH SKIP TO NEXT ROW +INITIAL +PATTERN (START UP+ DOWN+) +DEFINE +START AS TRUE, +UP AS price > PREV(price), +DOWN AS price < PREV(price) +); + +-- +-- Error cases +-- + +-- row pattern definition variable name must not appear more than once +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + ORDER BY tdate + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price), + UP AS price > PREV(price) +); + +-- pattern variable name must appear in DEFINE +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+ END) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- FRAME must start at current row when row patttern recognition is used +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING + INITIAL + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); + +-- SEEK is not supported +SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w + FROM stock + WINDOW w AS ( + PARTITION BY company + ORDER BY tdate + ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING + AFTER MATCH SKIP TO NEXT ROW + SEEK + PATTERN (START UP+ DOWN+) + DEFINE + START AS TRUE, + UP AS price > PREV(price), + DOWN AS price < PREV(price) +); -- 2.25.1 ----Next_Part(Sun_Oct_22_11_39_20_2023_140)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v10-0007-Allow-to-print-raw-parse-tree.patch" ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++----------------------- 1 file changed, 17 insertions(+), 40 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 5ee80c7632e..035932197a4 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3365,10 +3346,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4504,9 +4483,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); -- 2.50.1 (Apple Git-155) --Ot5x3ffkWEuxilWO-- ^ permalink raw reply [nested|flat] 687+ messages in thread
* [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics @ 2026-07-09 20:38 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 687+ messages in thread From: Nathan Bossart @ 2026-07-09 20:38 UTC (permalink / raw) --- src/backend/storage/lmgr/lock.c | 57 ++++++++++---------------------- src/tools/pgindent/typedefs.list | 1 - 2 files changed, 17 insertions(+), 41 deletions(-) diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 0608eee9eb2..c5943d7fc74 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -40,11 +40,11 @@ #include "miscadmin.h" #include "pg_trace.h" #include "pgstat.h" +#include "port/atomics.h" #include "storage/lmgr.h" #include "storage/proc.h" #include "storage/procarray.h" #include "storage/shmem.h" -#include "storage/spin.h" #include "storage/standby.h" #include "storage/subsystems.h" #include "utils/memutils.h" @@ -306,13 +306,7 @@ static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock); #define FastPathStrongLockHashPartition(hashcode) \ ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS) -typedef struct -{ - slock_t mutex; - uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS]; -} FastPathStrongRelationLockData; - -static FastPathStrongRelationLockData *FastPathStrongRelationLocks; +static pg_atomic_uint32 *FastPathStrongRelationLocks; static void LockManagerShmemRequest(void *arg); static void LockManagerShmemInit(void *arg); @@ -484,7 +478,8 @@ LockManagerShmemRequest(void *arg) ); ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data", - .size = sizeof(FastPathStrongRelationLockData), + .size = mul_size(sizeof(pg_atomic_uint32), + FAST_PATH_STRONG_LOCK_HASH_PARTITIONS), .ptr = (void **) (void *) &FastPathStrongRelationLocks, ); } @@ -492,7 +487,8 @@ LockManagerShmemRequest(void *arg) static void LockManagerShmemInit(void *arg) { - SpinLockInit(&FastPathStrongRelationLocks->mutex); + for (int i = 0; i < FAST_PATH_STRONG_LOCK_HASH_PARTITIONS; i++) + pg_atomic_init_u32(&FastPathStrongRelationLocks[i], 0); } /* @@ -992,11 +988,11 @@ LockAcquireExtended(const LOCKTAG *locktag, /* * LWLockAcquire acts as a memory sequencing point, so it's safe * to assume that any strong locker whose increment to - * FastPathStrongRelationLocks->counts becomes visible after we - * test it has yet to begin to transfer fast-path locks. + * FastPathStrongRelationLocks becomes visible after we test it + * has yet to begin to transfer fast-path locks. */ LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE); - if (FastPathStrongRelationLocks->count[fasthashcode] != 0) + if (pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) != 0) acquired = false; else acquired = FastPathGrantRelationLock(locktag->locktag_field2, @@ -1501,11 +1497,9 @@ RemoveLocalLock(LOCALLOCK *locallock) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } if (!hash_search(LockMethodLocalHash, @@ -1834,20 +1828,9 @@ BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode) Assert(StrongLockInProgress == NULL); Assert(locallock->holdsStrongLockCount == false); - /* - * Adding to a memory location is not atomic, so we take a spinlock to - * ensure we don't collide with someone else trying to bump the count at - * the same time. - * - * XXX: It might be worth considering using an atomic fetch-and-add - * instruction here, on architectures where that is supported. - */ - - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = true; StrongLockInProgress = locallock; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -1875,12 +1858,10 @@ AbortStrongLockAcquire(void) fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode); Assert(locallock->holdsStrongLockCount == true); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); locallock->holdsStrongLockCount = false; StrongLockInProgress = NULL; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); } /* @@ -3364,10 +3345,8 @@ LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0); - FastPathStrongRelationLocks->count[fasthashcode]--; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + Assert(pg_atomic_read_u32(&FastPathStrongRelationLocks[fasthashcode]) > 0); + pg_atomic_fetch_sub_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } } @@ -4502,9 +4481,7 @@ lock_twophase_recover(FullTransactionId fxid, uint16 info, { uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode); - SpinLockAcquire(&FastPathStrongRelationLocks->mutex); - FastPathStrongRelationLocks->count[fasthashcode]++; - SpinLockRelease(&FastPathStrongRelationLocks->mutex); + pg_atomic_fetch_add_u32(&FastPathStrongRelationLocks[fasthashcode], 1); } LWLockRelease(partitionLock); diff --git a/src/tools/pgindent/typedefs.list b/src/tools/pgindent/typedefs.list index 56c1f997f88..f4c989c8c30 100644 --- a/src/tools/pgindent/typedefs.list +++ b/src/tools/pgindent/typedefs.list @@ -846,7 +846,6 @@ FSMPageData FakeRelCacheEntry FakeRelCacheEntryData FastPathMeta -FastPathStrongRelationLockData FdwInfo FdwRoutine FetchDirection -- 2.50.1 (Apple Git-155) --Xf36GNcW+0xZNily-- ^ permalink raw reply [nested|flat] 687+ messages in thread
end of thread, other threads:[~2026-07-09 20:38 UTC | newest] Thread overview: 687+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2023-10-22 02:22 [PATCH v10 6/7] Row pattern recognition patch (tests). Tatsuo Ishii <ishii@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v1 8/8] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org> 2026-07-09 20:38 [PATCH v2 9/9] convert FastPathStrongRelationLocks to atomics Nathan Bossart <nathan@postgresql.org>
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