Patch "mm: workingset: fix premature shadow node shrinking with cgroups" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

mm: workingset: fix premature shadow node shrinking with cgroups

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mm-workingset-fix-premature-shadow-node-shrinking-with-cgroups.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johannes Weiner <[email protected]>
Date: Fri, 31 Mar 2017 15:11:52 -0700
Subject: mm: workingset: fix premature shadow node shrinking with cgroups

From: Johannes Weiner <[email protected]>

commit 0cefabdaf757a6455d75f00cb76874e62703ed18 upstream.

Commit 0a6b76dd23fa ("mm: workingset: make shadow node shrinker memcg aware") enabled cgroup-awareness in the shadow node shrinker, but forgot to also enable cgroup-awareness in the list_lru the shadow nodes sit on.

Consequently, all shadow nodes are sitting on a global (per-NUMA node) list, while the shrinker applies the limits according to the amount of cache in the cgroup its shrinking. The result is excessive pressure on the shadow nodes from cgroups that have very little cache.

Enable memcg-mode on the shadow node LRUs, such that per-cgroup limits are applied to per-cgroup lists.

---
 mm/workingset.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -492,7 +492,7 @@ static int __init workingset_init(void)
 	pr_info("workingset: timestamp_bits=%d max_order=%d bucket_order=%u\n",
 	       timestamp_bits, max_order, bucket_order);
 
-	ret = list_lru_init_key(&workingset_shadow_nodes, &shadow_nodes_key);
+	ret = __list_lru_init(&workingset_shadow_nodes, true, &shadow_nodes_key);
 	if (ret)
 		goto err;
 	ret = register_shrinker(&workingset_shadow_shrinker);

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/mm-rmap-fix-huge-file-mmap-accounting-in-the-memcg-stats.patch queue-4.9/mm-workingset-fix-premature-shadow-node-shrinking-with-cgroups.patch