The patch titled
Subject: mm: memcontrol: decouple reference counting from page accounting fix
has been added to the -mm tree. Its filename is
mm-memcontrol-decouple-reference-counting-from-page-accounting-fix.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-decouple-reference-counting-from-page-accounting-fix.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-decouple-reference-counting-from-page-accounting-fix.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm: memcontrol: decouple reference counting from page accounting fix
Moving tasks between mem cgroups with memory.move_charge_at_immigrate 3,
while swapping, crashes soon on mmotm (and so presumably on linux-next):
for example, spinlock found corrupted when lock_page_memcg() is called.
It's as if the mem cgroup structures have been freed too early.
Stab in the dark: what if all the accounting is right, except that the
css_put_many() in __mem_cgroup_clear_mc() is now (worse than) redundant?
Removing it fixes the crashes, but that's hardly surprising; and stats
temporarily hacked into mem_cgroup_css_alloc() and mem_cgroup_css_free()
showed that mem cgroups were not being leaked with this change.
Note: this removes the last call to css_put_many() from the tree; and
mm-memcg-slab-use-a-single-set-of-kmem_caches-for-all-accounted-allocations.patch
removes the last call to css_get_many(): now that their last references
have gone, I expect them soon to be freed from include/linux/cgroup.h.
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.2007302011450.2347@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 2 --
1 file changed, 2 deletions(-)
--- a/mm/memcontrol.c~mm-memcontrol-decouple-reference-counting-from-page-accounting-fix
+++ a/mm/memcontrol.c
@@ -5680,8 +5680,6 @@ static void __mem_cgroup_clear_mc(void)
if (!mem_cgroup_is_root(mc.to))
page_counter_uncharge(&mc.to->memory, mc.moved_swap);
- css_put_many(&mc.to->css, mc.moved_swap);
-
mc.moved_swap = 0;
}
memcg_oom_recover(from);
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
mm-memcontrol-decouple-reference-counting-from-page-accounting-fix.patch
