mm/kmemleak.c: make cond_resched() rate-limiting more efficient

commit 13ab183d138f607d885e995d625e58d47678bf97 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrew Morton 2017-12-14 15:32:31 -08:00 committed by Greg Kroah-Hartman
parent 2e454ae63b
commit 3cb026dc28

View File

@ -1442,7 +1442,7 @@ 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();
}
}