mm: treat memory.low value inclusive

If memcg's usage is equal to the memory.low value, avoid reclaiming from
this cgroup while there is a surplus of reclaimable memory.

This sounds more logical and also matches memory.high and memory.max
behavior: both are inclusive.

Empty cgroups are not considered protected, so MEMCG_LOW events are not
emitted for empty cgroups, if there is no more reclaimable memory in the
system.

Link: http://lkml.kernel.org/r/20180406122132.GA7185@castle
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Tejun Heo <tj@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:
Roman Gushchin 2018-06-07 17:06:26 -07:00 committed by Linus Torvalds
parent 230671533d
commit 5f93ad6743
1 changed files with 3 additions and 3 deletions

View File

@ -5344,14 +5344,14 @@ struct cgroup_subsys memory_cgrp_subsys = {
};
/**
* mem_cgroup_low - check if memory consumption is below the normal range
* mem_cgroup_low - check if memory consumption is in the normal range
* @root: the top ancestor of the sub-tree being checked
* @memcg: the memory cgroup to check
*
* WARNING: This function is not stateless! It can only be used as part
* of a top-down tree iteration, not for isolated queries.
*
* Returns %true if memory consumption of @memcg is below the normal range.
* Returns %true if memory consumption of @memcg is in the normal range.
*
* @root is exclusive; it is never low when looked at directly
*
@ -5445,7 +5445,7 @@ bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg)
elow = min(elow, parent_elow * low_usage / siblings_low_usage);
exit:
memcg->memory.elow = elow;
return usage < elow;
return usage && usage <= elow;
}
/**