From bc2a6e9d279c38afa1ccfd60ec93ad88eaf80b36 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Sat, 5 Apr 2025 16:20:13 +0200 Subject: [PATCH v25 5/6] adjust page alignment --- src/backend/storage/ipc/shmem.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c index 5d979423bd9..4a9a9606f2e 100644 --- a/src/backend/storage/ipc/shmem.c +++ b/src/backend/storage/ipc/shmem.c @@ -637,13 +637,22 @@ pg_get_shmem_allocations_numa(PG_FUNCTION_ARGS) while ((ent = (ShmemIndexEnt *) hash_seq_search(&hstat)) != NULL) { int i; + char *startptr, + *endptr; + Size total_len; - /* XXX I assume we use TYPEALIGN as a way to round to whole pages. - * It's a bit misleading to call that "aligned", no? */ + /* + * Calculate the range of OS pages used by this segment. The segment + * may start / end half-way through a page, we want to count these + * pages too. So we align the start/end pointers down/up, and then + * calculate the number of pages from that. + */ + startptr = (char *) TYPEALIGN_DOWN(os_page_size, ent->location); + endptr = (char *) TYPEALIGN(os_page_size, + (char *) ent->location + ent->allocated_size); + total_len = (endptr - startptr); - /* Get number of OS aligned pages */ - shm_ent_page_count - = TYPEALIGN(os_page_size, ent->allocated_size) / os_page_size; + shm_ent_page_count = total_len / os_page_size; /* * If we get ever 0xff back from kernel inquiry, then we probably have @@ -663,7 +672,7 @@ pg_get_shmem_allocations_numa(PG_FUNCTION_ARGS) { volatile uint64 touch pg_attribute_unused(); - page_ptrs[i] = (char *) ent->location + (i * os_page_size); + page_ptrs[i] = startptr + (i * os_page_size); if (firstNumaTouch) pg_numa_touch_mem_if_required(touch, page_ptrs[i]); -- 2.39.5