The patch titled
Subject: mm: memcontrol: fix memcg id ref counter on swap charge move
has been added to the -mm tree. Its filename is
mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch
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------------------------------------------------------
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: mm: memcontrol: fix memcg id ref counter on swap charge move
Since commit 73f576c04b941 swap entries do not pin memcg->css.refcnt
directly. Instead, they pin memcg->id.ref. So we should adjust the
reference counters accordingly when moving swap charges between cgroups.
Fixes: 73f576c04b941 ("mm: memcontrol: fix cgroup creation failure after many small jobs")
Link: http://lkml.kernel.org/r/3119b9b4526b18e6afcf55d3b4220437d642b00d.1470057819.git.vdavydov@xxxxxxxxxxxxx
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 24 ++++++++++++++++++------
1 file changed, 18 insertions(+), 6 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move
+++ a/mm/memcontrol.c
@@ -4069,9 +4069,9 @@ static struct cftype mem_cgroup_legacy_f
static DEFINE_IDR(mem_cgroup_idr);
-static void mem_cgroup_id_get(struct mem_cgroup *memcg)
+static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
- atomic_inc(&memcg->id.ref);
+ atomic_add(n, &memcg->id.ref);
}
static struct mem_cgroup *mem_cgroup_id_get_active(struct mem_cgroup *memcg)
@@ -4081,9 +4081,9 @@ static struct mem_cgroup *mem_cgroup_id_
return memcg;
}
-static void mem_cgroup_id_put(struct mem_cgroup *memcg)
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
{
- if (atomic_dec_and_test(&memcg->id.ref)) {
+ if (atomic_sub_and_test(n, &memcg->id.ref)) {
idr_remove(&mem_cgroup_idr, memcg->id.id);
memcg->id.id = 0;
@@ -4092,6 +4092,16 @@ static void mem_cgroup_id_put(struct mem
}
}
+static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_get_many(memcg, 1);
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_put_many(memcg, 1);
+}
+
/**
* mem_cgroup_from_id - look up a memcg from a memcg id
* @id: the memcg id to look up
@@ -4726,6 +4736,8 @@ static void __mem_cgroup_clear_mc(void)
if (!mem_cgroup_is_root(mc.from))
page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
+ mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
/*
* we charged both to->memory and to->memsw, so we
* should uncharge to->memory.
@@ -4733,9 +4745,9 @@ 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.from->css, mc.moved_swap);
+ mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+ css_put_many(&mc.to->css, mc.moved_swap);
- /* we've already done css_get(mc.to) */
mc.moved_swap = 0;
}
memcg_oom_recover(from);
_
Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are
mm-memcontrol-fix-swap-counter-leak-on-swapout-from-offline-cgroup.patch
mm-memcontrol-fix-memcg-id-ref-counter-on-swap-charge-move.patch
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