Re: Bertrand Drouvot
> Yes, something like:
>
> diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
> index c9ae3b45b76..070ad2f13e7 100644
> --- a/src/backend/storage/ipc/shmem.c
> +++ b/src/backend/storage/ipc/shmem.c
> @@ -689,8 +689,17 @@ pg_get_shmem_allocations_numa(PG_FUNCTION_ARGS)
> CHECK_FOR_INTERRUPTS();
> }
>
> - if (pg_numa_query_pages(0, shm_ent_page_count, page_ptrs,
> pages_status) == -1)
> - elog(ERROR, "failed NUMA pages inquiry status: %m");
> + #define NUMA_QUERY_CHUNK_SIZE 16 /* has to be <=
> DO_PAGES_STAT_CHUNK_NR (do_pages_stat())*/
> +
> + for (uint64 chunk_start = 0; chunk_start <
> shm_ent_page_count; chunk_start += NUMA_QUERY_CHUNK_SIZE) {
> + uint64 chunk_size = Min(NUMA_QUERY_CHUNK_SIZE,
> shm_ent_page_count - chunk_start);
> +
> + if (pg_numa_query_pages(0, chunk_size,
> &page_ptrs[chunk_start],
> +
> &pages_status[chunk_start]) == -1)
> + elog(ERROR, "failed NUMA pages inquiry
> status: %m");
> + }
> +
> + #undef NUMA_QUERY_CHUNK_SIZE
I uploaded a variant of this patch to Debian and it seems to have fixed the
issue:
https://buildd.debian.org/status/package.php?p=postgresql-18&suite=experimental
(No reply from linux-mm yet.)
Christoph
Work around a Linux bug in move_pages
In 32-bit mode on 64-bit kernels, move_pages() does not correctly advance to
the next chunk. Work around by not asking for more than 16 pages at once so
move_pages() internal loop is not executed more than once.
https://www.postgresql.org/message-id/flat/a3a4fe3d-1a80-4e03-aa8e-150ee15f6c35%40vondra.me#6abe7eaa802b5b07bb70cc3229e63a9f
https://marc.info/?l=linux-mm&m=175077821909222&w=2
--- a/contrib/pg_buffercache/pg_buffercache_pages.c
+++ b/contrib/pg_buffercache/pg_buffercache_pages.c
@@ -390,8 +390,15 @@ pg_buffercache_numa_pages(PG_FUNCTION_AR
memset(os_page_status, 0xff, sizeof(int) * os_page_count);
/* Query NUMA status for all the pointers */
- if (pg_numa_query_pages(0, os_page_count, os_page_ptrs,
os_page_status) == -1)
- elog(ERROR, "failed NUMA pages inquiry: %m");
+#define NUMA_QUERY_CHUNK_SIZE 16 /* has to be <= DO_PAGES_STAT_CHUNK_NR
(do_pages_stat())*/
+ for (uint64 chunk_start = 0; chunk_start < os_page_count;
chunk_start += NUMA_QUERY_CHUNK_SIZE) {
+ uint64 chunk_size = Min(NUMA_QUERY_CHUNK_SIZE,
os_page_count - chunk_start);
+
+ if (pg_numa_query_pages(0, chunk_size,
&os_page_ptrs[chunk_start],
+ &os_page_status[chunk_start])
== -1)
+ elog(ERROR, "failed NUMA pages inquiry status:
%m");
+ }
+#undef NUMA_QUERY_CHUNK_SIZE
/* Initialize the multi-call context, load entries about
buffers */
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -689,8 +689,15 @@ pg_get_shmem_allocations_numa(PG_FUNCTIO
CHECK_FOR_INTERRUPTS();
}
- if (pg_numa_query_pages(0, shm_ent_page_count, page_ptrs,
pages_status) == -1)
- elog(ERROR, "failed NUMA pages inquiry status: %m");
+#define NUMA_QUERY_CHUNK_SIZE 16 /* has to be <= DO_PAGES_STAT_CHUNK_NR
(do_pages_stat())*/
+ for (uint64 chunk_start = 0; chunk_start < shm_ent_page_count;
chunk_start += NUMA_QUERY_CHUNK_SIZE) {
+ uint64 chunk_size = Min(NUMA_QUERY_CHUNK_SIZE,
shm_ent_page_count - chunk_start);
+
+ if (pg_numa_query_pages(0, chunk_size,
&page_ptrs[chunk_start],
+ &pages_status[chunk_start]) ==
-1)
+ elog(ERROR, "failed NUMA pages inquiry status:
%m");
+ }
+#undef NUMA_QUERY_CHUNK_SIZE
/* Count number of NUMA nodes used for this shared memory entry
*/
memset(nodes, 0, sizeof(Size) * (max_nodes + 1));
