From 5f93ad67436b3da8312db5ad4eedfa739c00787f Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 7 Jun 2018 17:06:26 -0700 Subject: [PATCH] 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 Acked-by: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d0261059aab9..8bab4660e6aa 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -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; } /**