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pgsql: Silence valgrind about pg_numa_touch_mem_if_required 2+ messages / 1 participants [nested] [flat]
* pgsql: Silence valgrind about pg_numa_touch_mem_if_required @ 2025-07-01 10:34 Tomas Vondra <tomas.vondra@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Tomas Vondra @ 2025-07-01 10:34 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence valgrind about pg_numa_touch_mem_if_required When querying NUMA status of pages in shared memory, we need to touch the memory first to get valid results. This may trigger valgrind reports, because some of the memory (e.g. unpinned buffers) may be marked as noaccess. Solved by adding a valgrind suppresion. An alternative would be to adjust the access/noaccess status before touching the memory, but that seems far too invasive. It would require all those places to have detailed knowledge of what the shared memory stores. The pg_numa_touch_mem_if_required() macro is replaced with a function. Macros are invisible to suppressions, so it'd have to suppress reports for the caller - e.g. pg_get_shmem_allocations_numa(). So we'd suppress reports for the whole function, and that seems to heavy-handed. It might easily hide other valid issues. Reviewed-by: Christoph Berg <myon@debian.org> Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com> Discussion: https://postgr.es/m/aEtDozLmtZddARdB@msg.df7cb.de Backpatch-through: 18 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/81f287dc923f565722f46b18d71969926bc3c64f Modified Files -------------- contrib/pg_buffercache/pg_buffercache_pages.c | 3 +-- src/backend/storage/ipc/shmem.c | 4 +--- src/include/port/pg_numa.h | 10 +++++++--- src/tools/valgrind.supp | 14 ++++++++++++++ 4 files changed, 23 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: Silence valgrind about pg_numa_touch_mem_if_required @ 2025-07-01 10:34 Tomas Vondra <tomas.vondra@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Tomas Vondra @ 2025-07-01 10:34 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Silence valgrind about pg_numa_touch_mem_if_required When querying NUMA status of pages in shared memory, we need to touch the memory first to get valid results. This may trigger valgrind reports, because some of the memory (e.g. unpinned buffers) may be marked as noaccess. Solved by adding a valgrind suppresion. An alternative would be to adjust the access/noaccess status before touching the memory, but that seems far too invasive. It would require all those places to have detailed knowledge of what the shared memory stores. The pg_numa_touch_mem_if_required() macro is replaced with a function. Macros are invisible to suppressions, so it'd have to suppress reports for the caller - e.g. pg_get_shmem_allocations_numa(). So we'd suppress reports for the whole function, and that seems to heavy-handed. It might easily hide other valid issues. Reviewed-by: Christoph Berg <myon@debian.org> Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com> Discussion: https://postgr.es/m/aEtDozLmtZddARdB@msg.df7cb.de Backpatch-through: 18 Branch ------ REL_18_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/14e52227e57885d1a983d9f2515b569d3180c93d Modified Files -------------- contrib/pg_buffercache/pg_buffercache_pages.c | 3 +-- src/backend/storage/ipc/shmem.c | 4 +--- src/include/port/pg_numa.h | 10 +++++++--- src/tools/valgrind.supp | 14 ++++++++++++++ 4 files changed, 23 insertions(+), 8 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2025-07-01 10:34 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2025-07-01 10:34 pgsql: Silence valgrind about pg_numa_touch_mem_if_required Tomas Vondra <tomas.vondra@postgresql.org> 2025-07-01 10:34 pgsql: Silence valgrind about pg_numa_touch_mem_if_required Tomas Vondra <tomas.vondra@postgresql.org>
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