Patch "mm: memcontrol: let v2 cgroups follow changes in system swappiness" has been added to the 4.5-stable tree

Patch "mm: memcontrol: let v2 cgroups follow changes in system swappiness" has been added to the 4.5-stable tree

[gregkh]

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

    mm: memcontrol: let v2 cgroups follow changes in system swappiness

to the 4.5-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-memcontrol-let-v2-cgroups-follow-changes-in-system-swappiness.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4550c4e157ca3da929593bb6c64080a59141af35 Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Thu, 5 May 2016 16:22:03 -0700
Subject: mm: memcontrol: let v2 cgroups follow changes in system swappiness

From: Johannes Weiner <hannes@cmpxchg.org>

commit 4550c4e157ca3da929593bb6c64080a59141af35 upstream.

Cgroup2 currently doesn't have a per-cgroup swappiness setting.  We
might want to add one later - that's a different discussion - but until
we do, the cgroups should always follow the system setting.  Otherwise
it will be unchangeably set to whatever the ancestor inherited from the
system setting at the time of cgroup creation.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 2b83359c19ca..0a4cd4703f40 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -533,6 +533,10 @@ static inline swp_entry_t get_swap_page(void)
 #ifdef CONFIG_MEMCG
 static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
 {
+	/* Cgroup2 doesn't have per-cgroup swappiness */
+	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
+		return vm_swappiness;
+
 	/* root ? */
 	if (mem_cgroup_disabled() || !memcg->css.parent)
 		return vm_swappiness;


Patches currently in stable-queue which might be from hannes@cmpxchg.org are

queue-4.5/mm-memcontrol-let-v2-cgroups-follow-changes-in-system-swappiness.patch