mm: change per-VMA lock statistics to be disabled by default

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/[email protected] Fixes: 52f2386 ("mm: introduce per-VMA lock statistics") Signed-off-by: Suren Baghdasaryan <[email protected]> Suggested-by: Linus Torvalds <[email protected]> Reviewed-by: Lorenzo Stoakes <[email protected]> Acked-by: Vlastimil Babka <[email protected]> Reviewed-by: David Hildenbrand <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
niw · May 3, 2023 · 6152e53 · 6152e53
1 parent 3628d2b
commit 6152e53
Showing 1 changed file with 8 additions and 2 deletions.
diff --git a/mm/Kconfig.debug b/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.