From 13ab183d138f607d885e995d625e58d47678bf97 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 14 Dec 2017 15:32:31 -0800
Subject: [PATCH] mm/kmemleak.c: make cond_resched() rate-limiting more efficient
Git-commit: 13ab183d138f607d885e995d625e58d47678bf97
Patch-mainline: v4.15-rc4
References: bsc#1051510
Commit bde5f6bc68db ("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@linux-foundation.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
mm/kmemleak.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 3d4781756d50..d73c14294f3a 100644
--- a/mm/kmemleak.c
+++ b/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();
}
}
--
2.18.0