From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: mm/kmemleak.c: make cond_resched() rate-limiting more efficient
bde5f6bc68db5 ("kmemleak: add scheduling point to kmemleak_scan()") tries
to rate-limit the frequency of cond_resched() calls, but does it in a way
which might incur an expensive division operation in the inner loop.
Simplify this.
Fixes: bde5f6bc68db5 ("kmemleak: add scheduling point to kmemleak_scan()")
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Yisheng Xie <xieyisheng1@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kmemleak.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN mm/kmemleak.c~mm-kmemleakc-make-cond_resched-rate-limiting-more-efficient mm/kmemleak.c
--- a/mm/kmemleak.c~mm-kmemleakc-make-cond_resched-rate-limiting-more-efficient
+++ a/mm/kmemleak.c
@@ -1523,7 +1523,7 @@ static void kmemleak_scan(void)
if (page_count(page) == 0)
continue;
scan_block(page, page + 1, NULL);
- if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page))))
+ if (!(pfn & 63))
cond_resched();
}
}
_
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