diff options
authorJohannes Weiner <hannes@cmpxchg.org>2019-05-14 15:47:15 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:53 -0700
commitdef0fdae813dbbbbb588bfc5f52856be2e842b35 (patch)
parent42a300353577ccc17ecc627b8570a89fa1678bec (diff)
mm: memcontrol: fix NUMA round-robin reclaim at intermediate level
When a cgroup is reclaimed on behalf of a configured limit, reclaim needs to round-robin through all NUMA nodes that hold pages of the memcg in question. However, when assembling the mask of candidate NUMA nodes, the code only consults the *local* cgroup LRU counters, not the recursive counters for the entire subtree. Cgroup limits are frequently configured against intermediate cgroups that do not have memory on their own LRUs. In this case, the node mask will always come up empty and reclaim falls back to scanning only the current node. If a cgroup subtree has some memory on one node but the processes are bound to another node afterwards, the limit reclaim will never age or reclaim that memory anymore. To fix this, use the recursive LRU counts for a cgroup subtree to determine which nodes hold memory of that cgroup. The code has been broken like this forever, so it doesn't seem to be a problem in practice. I just noticed it while reviewing the way the LRU counters are used in general. Link: http://lkml.kernel.org/r/20190412151507.2769-5-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Shakeel Butt <shakeelb@google.com> Reviewed-by: Roman Gushchin <guro@fb.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 files changed, 4 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7a764cbf8495..e50a2db5b4ff 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1507,13 +1507,13 @@ static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
- if (lruvec_page_state_local(lruvec, NR_INACTIVE_FILE) ||
- lruvec_page_state_local(lruvec, NR_ACTIVE_FILE))
+ if (lruvec_page_state(lruvec, NR_INACTIVE_FILE) ||
+ lruvec_page_state(lruvec, NR_ACTIVE_FILE))
return true;
if (noswap || !total_swap_pages)
return false;
- if (lruvec_page_state_local(lruvec, NR_INACTIVE_ANON) ||
- lruvec_page_state_local(lruvec, NR_ACTIVE_ANON))
+ if (lruvec_page_state(lruvec, NR_INACTIVE_ANON) ||
+ lruvec_page_state(lruvec, NR_ACTIVE_ANON))
return true;
return false;