Jiang Biao d5dabd6339 fs/mbcache.c: make count_objects() more robust
When running ltp stress test for 7*24 hours, vmscan occasionally emits
the following warning continuously:

  mb_cache_scan+0x0/0x3f0 negative objects to delete
  nr=-9232265467809300450
  ...

Tracing shows the freeable(mb_cache_count returns) is -1, which causes
the continuous accumulation and overflow of total_scan.

This patch makes sure that mb_cache_count() cannot return a negative
value, which makes the mbcache shrinker more robust.

Link: http://lkml.kernel.org/r/1511753419-52328-1-git-send-email-jiang.biao2@zte.com.cn
Signed-off-by: Jiang Biao <jiang.biao2@zte.com.cn>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <zhong.weidong@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-29 18:40:43 -08:00
..
2017-11-15 18:21:06 -08:00
2017-08-24 13:23:03 -07:00
2017-11-14 14:44:04 -08:00
2017-11-16 11:41:22 -08:00
2017-11-17 09:51:57 -08:00
2017-11-18 11:22:04 -08:00
2017-11-18 11:22:04 -08:00
2017-09-04 19:05:15 -04:00
2017-11-15 18:21:04 -08:00