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Patch "mm, memcg: fix mem_cgroup_swapout() for THPs" has been added to the 4.14-stable tree

PATCH [email protected] 1 participant 1 message Dec 4, 2017

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

mm, memcg: fix mem_cgroup_swapout() for THPs

to the 4.14-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-memcg-fix-mem_cgroup_swapout-for-thps.patch
and it can be found in the queue-4.14 subdirectory.

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

Quoted 1 line

From d08afa149acfd00871484ada6dabc3880524cd1c Mon Sep 17 00:00:00 2001

From: Shakeel Butt <[email protected]>
Date: Wed, 29 Nov 2017 16:11:15 -0800
Subject: mm, memcg: fix mem_cgroup_swapout() for THPs

From: Shakeel Butt <[email protected]>

commit d08afa149acfd00871484ada6dabc3880524cd1c upstream.

Commit d6810d730022 ("memcg, THP, swap: make mem_cgroup_swapout() support THP") changed mem_cgroup_swapout() to support transparent huge page (THP).

However the patch missed one location which should be changed for correctly handling THPs. The resulting bug will cause the memory cgroups whose THPs were swapped out to become zombies on deletion.

Fixes d6810d730022 ("memcg, THP, swap: make mem_cgroup_swapout() support THP")
Cc Huang Ying <[email protected]>
Cc Vladimir Davydov <[email protected]>
Cc Greg Thelen <[email protected]>
---
 mm/memcontrol.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
mm/memcontrol.c +1 -1
@@ -6044,7 +6044,7 @@ void mem_cgroup_swapout(struct page *pag
 	memcg_check_events(memcg, page);
 
 	if (!mem_cgroup_is_root(memcg))
-		css_put(&memcg->css);
+		css_put_many(&memcg->css, nr_entries);
 }
 
 /**

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

queue-4.14/mm-memcg-fix-mem_cgroup_swapout-for-thps.patch