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help / color / mirror / Atom feedFrom: Justin Pryzby <[email protected]>
Subject: [PATCH v7] add GUC: huge_pages_active
Date: Mon, 23 Jan 2023 18:33:51 -0600
This is useful to show the current state of huge pages when
huge_pages=try. The effective status is not otherwise visible without
OS level tools like gdb or /proc/N/smaps.
https://www.postgresql.org/message-id/flat/TU4PR8401MB1152EBB0D271F827E2E37A01EECC9@TU4PR8401MB1152....
---
doc/src/sgml/config.sgml | 21 ++++++++++++++++++++-
src/backend/port/sysv_shmem.c | 7 +++++++
src/backend/port/win32_shmem.c | 4 ++++
src/backend/storage/ipc/ipci.c | 2 ++
src/backend/utils/misc/guc_tables.c | 20 ++++++++++++++++++++
src/include/storage/pg_shmem.h | 5 +++--
6 files changed, 56 insertions(+), 3 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 096be7cb8cc..de74d3d1a81 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -1728,7 +1728,8 @@ include_dir 'conf.d'
server will try to request huge pages, but fall back to the default if
that fails. With <literal>on</literal>, failure to request huge pages
will prevent the server from starting up. With <literal>off</literal>,
- huge pages will not be requested.
+ huge pages will not be requested. The actual state of huge pages is
+ indicated by the server variable <xref linkend="guc-huge-pages-status"/>.
</para>
<para>
@@ -10710,6 +10711,24 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
</listitem>
</varlistentry>
+ <varlistentry id="guc-huge-pages-status" xreflabel="huge_pages_status">
+ <term><varname>huge_pages_status</varname> (<type>enum</type>)
+ <indexterm>
+ <primary><varname>huge_pages_status</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Reports the state of huge pages in the current instance:
+ <literal>on</literal>, <literal>off</literal>, or (if displayed with
+ <literal>postgres -C</literal>) <literal>unknown</literal>.
+ This parameter is useful to determine whether allocation of huge pages
+ was successful when <literal>huge_pages=try</literal>.
+ See <xref linkend="guc-huge-pages"/> for more information.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-integer-datetimes" xreflabel="integer_datetimes">
<term><varname>integer_datetimes</varname> (<type>boolean</type>)
<indexterm>
diff --git a/src/backend/port/sysv_shmem.c b/src/backend/port/sysv_shmem.c
index eaba244bc9c..a958f75f7a4 100644
--- a/src/backend/port/sysv_shmem.c
+++ b/src/backend/port/sysv_shmem.c
@@ -627,6 +627,9 @@ CreateAnonymousSegment(Size *size)
}
#endif
+ SetConfigOption("huge_pages_status", ptr == MAP_FAILED ? "off" : "on",
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
+
if (ptr == MAP_FAILED && huge_pages != HUGE_PAGES_ON)
{
/*
@@ -737,7 +740,11 @@ PGSharedMemoryCreate(Size size,
sysvsize = sizeof(PGShmemHeader);
}
else
+ {
sysvsize = size;
+ SetConfigOption("huge_pages_status", "off",
+ PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
+ }
/*
* Loop till we find a free IPC key. Trust CreateDataDirLockFile() to
diff --git a/src/backend/port/win32_shmem.c b/src/backend/port/win32_shmem.c
index 62e08074770..199f2e23a13 100644
--- a/src/backend/port/win32_shmem.c
+++ b/src/backend/port/win32_shmem.c
@@ -327,6 +327,10 @@ retry:
Sleep(1000);
continue;
}
+
+ SetConfigOption("huge_pages_status", (flProtect & SEC_LARGE_PAGES) ?
+ "on" : "off", PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
+
break;
}
diff --git a/src/backend/storage/ipc/ipci.c b/src/backend/storage/ipc/ipci.c
index 8f1ded7338f..f760675691a 100644
--- a/src/backend/storage/ipc/ipci.c
+++ b/src/backend/storage/ipc/ipci.c
@@ -190,6 +190,8 @@ CreateSharedMemoryAndSemaphores(void)
*/
seghdr = PGSharedMemoryCreate(size, &shim);
+ Assert(strcmp("unknown", GetConfigOption("huge_pages_status", false, false)) != 0);
+
InitShmemAccess(seghdr);
/*
diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.c
index 0a399afa8ca..a6b7fd28e68 100644
--- a/src/backend/utils/misc/guc_tables.c
+++ b/src/backend/utils/misc/guc_tables.c
@@ -366,6 +366,13 @@ static const struct config_enum_entry huge_pages_options[] = {
{NULL, 0, false}
};
+static const struct config_enum_entry huge_pages_status_options[] = {
+ {"off", HUGE_PAGES_OFF, false},
+ {"on", HUGE_PAGES_ON, false},
+ {"unknown", HUGE_PAGES_UNKNOWN, false},
+ {NULL, 0, false}
+};
+
static const struct config_enum_entry recovery_prefetch_options[] = {
{"off", RECOVERY_PREFETCH_OFF, false},
{"on", RECOVERY_PREFETCH_ON, false},
@@ -554,6 +561,8 @@ int ssl_renegotiation_limit;
int huge_pages = HUGE_PAGES_TRY;
int huge_page_size;
+int huge_pages_status = HUGE_PAGES_UNKNOWN;
+
/*
* These variables are all dummies that don't do anything, except in some
* cases provide the value for SHOW to display. The real state is elsewhere
@@ -4889,6 +4898,17 @@ struct config_enum ConfigureNamesEnum[] =
NULL, NULL, NULL
},
+ {
+ {"huge_pages_status", PGC_INTERNAL, PRESET_OPTIONS,
+ gettext_noop("Indicates the status of huge pages."),
+ NULL,
+ GUC_NOT_IN_SAMPLE | GUC_DISALLOW_IN_FILE
+ },
+ &huge_pages_status,
+ HUGE_PAGES_UNKNOWN, huge_pages_status_options,
+ NULL, NULL, NULL
+ },
+
{
{"recovery_prefetch", PGC_SIGHUP, WAL_RECOVERY,
gettext_noop("Prefetch referenced blocks during recovery."),
diff --git a/src/include/storage/pg_shmem.h b/src/include/storage/pg_shmem.h
index 4dd05f156d5..bfda42b0b26 100644
--- a/src/include/storage/pg_shmem.h
+++ b/src/include/storage/pg_shmem.h
@@ -46,12 +46,13 @@ extern PGDLLIMPORT int shared_memory_type;
extern PGDLLIMPORT int huge_pages;
extern PGDLLIMPORT int huge_page_size;
-/* Possible values for huge_pages */
+/* Possible values for huge_pages/huge_pages_status */
typedef enum
{
HUGE_PAGES_OFF,
HUGE_PAGES_ON,
- HUGE_PAGES_TRY
+ HUGE_PAGES_TRY, /* only for huge_pages */
+ HUGE_PAGES_UNKNOWN /* only for huge_pages_status */
} HugePagesType;
/* Possible values for shared_memory_type */
--
2.34.1
--PELMulVtG1KW7XV6--
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Subject: Re: [PATCH v7] add GUC: huge_pages_active
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