mm: memcontrol: restore proper dirty throttling when memory.high changes
authorJohannes Weiner <hannes@cmpxchg.org>
Fri, 7 Aug 2020 06:22:12 +0000 (23:22 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 7 Aug 2020 18:33:26 +0000 (11:33 -0700)
commit19ce33acbbd03c371f2d4b533879c4755686f95f
tree5d92aa74bbce27717edea2da2578dc14e300d2fe
parent1378b37d03e8147c67fde60caf0474ea879163d8
mm: memcontrol: restore proper dirty throttling when memory.high changes

Commit 8c8c383c04f6 ("mm: memcontrol: try harder to set a new
memory.high") inadvertently removed a callback to recalculate the
writeback cache size in light of a newly configured memory.high limit.

Without letting the writeback cache know about a potentially heavily
reduced limit, it may permit too many dirty pages, which can cause
unnecessary reclaim latencies or even avoidable OOM situations.

This was spotted while reading the code, it hasn't knowingly caused any
problems in practice so far.

Fixes: 8c8c383c04f6 ("mm: memcontrol: try harder to set a new memory.high")
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Roman Gushchin <guro@fb.com>
Link: http://lkml.kernel.org/r/20200728135210.379885-1-hannes@cmpxchg.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/memcontrol.c