The patch titled
Subject: mm: change per-VMA lock statistics to be disabled by default
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-change-per-vma-lock-statistics-to-be-disabled-by-default.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-change-per-vma-lock-statistics-to-be-disabled-by-default.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: mm: change per-VMA lock statistics to be disabled by default
Date: Fri, 28 Apr 2023 10:35:33 -0700
Change CONFIG_PER_VMA_LOCK_STATS to be disabled by default, as most users
don't need it. Add configuration help to clarify its usage.
Link: https://lkml.kernel.org/r/20230428173533.18158-1-surenb@xxxxxxxxxx
Fixes: 52f238653e45 ("mm: introduce per-VMA lock statistics")
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/Kconfig.debug | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/Kconfig.debug~mm-change-per-vma-lock-statistics-to-be-disabled-by-default
+++ a/mm/Kconfig.debug
@@ -274,6 +274,12 @@ config DEBUG_KMEMLEAK_AUTO_SCAN
config PER_VMA_LOCK_STATS
bool "Statistics for per-vma locks"
depends on PER_VMA_LOCK
- default y
help
- Statistics for per-vma locks.
+ Say Y here to enable success, retry and failure counters of page
+ faults handled under protection of per-vma locks. When enabled, the
+ counters are exposed in /proc/vmstat. This information is useful for
+ kernel developers to evaluate effectiveness of per-vma locks and to
+ identify pathological cases. Counting these events introduces a small
+ overhead in the page fault path.
+
+ If in doubt, say N.
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
mm-change-per-vma-lock-statistics-to-be-disabled-by-default.patch
