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kmemleak: add scheduling point to kmemleak_scan()

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kmemleak_scan() will scan struct page for each node and it can be really
large and resulting in a soft lockup.  We have seen a soft lockup when
do scan while compile kernel:

  watchdog: BUG: soft lockup - CPU#53 stuck for 22s! [bash:10287]
 [...]
  Call Trace:
   kmemleak_scan+0x21a/0x4c0
   kmemleak_write+0x312/0x350
   full_proxy_write+0x5a/0xa0
   __vfs_write+0x33/0x150
   vfs_write+0xad/0x1a0
   SyS_write+0x52/0xc0
   do_syscall_64+0x61/0x1a0
   entry_SYSCALL64_slow_path+0x25/0x25

Fix this by adding cond_resched every MAX_SCAN_SIZE.

Link: http://lkml.kernel.org/r/1511439788-20099-1-git-send-email-xieyisheng1@huawei.com
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: 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>
This commit is contained in:
Yisheng Xie 2017-11-29 16:11:08 -08:00 committed by Linus Torvalds
parent edbddb83a1
commit bde5f6bc68
1 changed files with 2 additions and 0 deletions
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2
mm/kmemleak.c
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@ -1523,6 +1523,8 @@ static void kmemleak_scan(void)
if (page_count(page) == 0) if (page_count(page) == 0)
continue; continue;
scan_block(page, page + 1, NULL); scan_block(page, page + 1, NULL);
if (!(pfn % (MAX_SCAN_SIZE / sizeof(*page))))
cond_resched();
} }
} }
put_online_mems(); put_online_mems();