mm: treat memory.low value inclusive (5f93ad67) · Commits · 戴 / test

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>

mm/memcontrol.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -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;
		}

		/**

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