* [merged mm-hotfixes-stable] mm-fix-for-negative-counter-nr_file_hugepages.patch removed from -mm tree
@ 2023-11-15 23:30 Andrew Morton
0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2023-11-15 23:30 UTC (permalink / raw)
To: mm-commits, willy, stable, shy828301, riel, hannes, david, shr, akpm
The quilt patch titled
Subject: mm: fix for negative counter: nr_file_hugepages
has been removed from the -mm tree. Its filename was
mm-fix-for-negative-counter-nr_file_hugepages.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Stefan Roesch <shr@devkernel.io>
Subject: mm: fix for negative counter: nr_file_hugepages
Date: Mon, 6 Nov 2023 10:19:18 -0800
While qualifiying the 6.4 release, the following warning was detected in
messages:
vmstat_refresh: nr_file_hugepages -15664
The warning is caused by the incorrect updating of the NR_FILE_THPS
counter in the function split_huge_page_to_list. The if case is checking
for folio_test_swapbacked, but the else case is missing the check for
folio_test_pmd_mappable. The other functions that manipulate the counter
like __filemap_add_folio and filemap_unaccount_folio have the
corresponding check.
I have a test case, which reproduces the problem. It can be found here:
https://github.com/sroeschus/testcase/blob/main/vmstat_refresh/madv.c
The test case reproduces on an XFS filesystem. Running the same test
case on a BTRFS filesystem does not reproduce the problem.
AFAIK version 6.1 until 6.6 are affected by this problem.
[akpm@linux-foundation.org: whitespace fix]
[shr@devkernel.io: test for folio_test_pmd_mappable()]
Link: https://lkml.kernel.org/r/20231108171517.2436103-1-shr@devkernel.io
Link: https://lkml.kernel.org/r/20231106181918.1091043-1-shr@devkernel.io
Signed-off-by: Stefan Roesch <shr@devkernel.io>
Co-debugged-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/huge_memory.c | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
--- a/mm/huge_memory.c~mm-fix-for-negative-counter-nr_file_hugepages
+++ a/mm/huge_memory.c
@@ -2769,13 +2769,15 @@ int split_huge_page_to_list(struct page
int nr = folio_nr_pages(folio);
xas_split(&xas, folio, folio_order(folio));
- if (folio_test_swapbacked(folio)) {
- __lruvec_stat_mod_folio(folio, NR_SHMEM_THPS,
- -nr);
- } else {
- __lruvec_stat_mod_folio(folio, NR_FILE_THPS,
- -nr);
- filemap_nr_thps_dec(mapping);
+ if (folio_test_pmd_mappable(folio)) {
+ if (folio_test_swapbacked(folio)) {
+ __lruvec_stat_mod_folio(folio,
+ NR_SHMEM_THPS, -nr);
+ } else {
+ __lruvec_stat_mod_folio(folio,
+ NR_FILE_THPS, -nr);
+ filemap_nr_thps_dec(mapping);
+ }
}
}
_
Patches currently in -mm which might be from shr@devkernel.io are
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2023-11-15 23:30 UTC | newest]
Thread overview: (only message) (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-11-15 23:30 [merged mm-hotfixes-stable] mm-fix-for-negative-counter-nr_file_hugepages.patch removed from -mm tree Andrew Morton
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).