From: Andrew Morton <akpm@linux-foundation.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>,
hannes@cmpxchg.org, vdavydov.dev@gmail.com,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure
Date: Thu, 26 Jul 2018 16:25:12 -0700 [thread overview]
Message-ID: <20180726162512.6056b5d7c1d2a5fbff6ce214@linux-foundation.org> (raw)
In-Reply-To: <20180413125101.GO17484@dhcp22.suse.cz>
On Fri, 13 Apr 2018 14:51:01 +0200 Michal Hocko <mhocko@kernel.org> wrote:
> On Fri 13-04-18 14:14:33, Michal Hocko wrote:
> [...]
> > Well, this is probably a matter of taste. I will not argue. I will not
> > object if Johannes is OK with your patch. But the whole thing confused
> > hell out of me so I would rather un-clutter it...
>
> In other words, this
>
This discussion has rather petered out. afaict we're waiting for
hannes to offer an opinion?
From: Kirill Tkhai <ktkhai@virtuozzo.com>
Subject: memcg: remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure
In case of memcg_online_kmem() failure, memcg_cgroup::id remains hashed in
mem_cgroup_idr even after memcg memory is freed. This leads to leak of ID
in mem_cgroup_idr.
This patch adds removal into mem_cgroup_css_alloc(), which fixes the
problem. For better readability, it adds a generic helper which is used
in mem_cgroup_alloc() and mem_cgroup_id_put_many() as well.
Link: http://lkml.kernel.org/r/152354470916.22460.14397070748001974638.stgit@localhost.localdomain
Fixes 73f576c04b94 ("mm: memcontrol: fix cgroup creation failure after many small jobs")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/memcontrol.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff -puN mm/memcontrol.c~memcg-remove-memcg_cgroup-id-from-idr-on-mem_cgroup_css_alloc-failure mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-remove-memcg_cgroup-id-from-idr-on-mem_cgroup_css_alloc-failure
+++ a/mm/memcontrol.c
@@ -4037,6 +4037,14 @@ static struct cftype mem_cgroup_legacy_f
static DEFINE_IDR(mem_cgroup_idr);
+static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
+{
+ if (memcg->id.id > 0) {
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
+ memcg->id.id = 0;
+ }
+}
+
static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
{
VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
@@ -4047,8 +4055,7 @@ static void mem_cgroup_id_put_many(struc
{
VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
if (atomic_sub_and_test(n, &memcg->id.ref)) {
- idr_remove(&mem_cgroup_idr, memcg->id.id);
- memcg->id.id = 0;
+ mem_cgroup_id_remove(memcg);
/* Memcg ID pins CSS */
css_put(&memcg->css);
@@ -4185,8 +4192,7 @@ static struct mem_cgroup *mem_cgroup_all
idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
return memcg;
fail:
- if (memcg->id.id > 0)
- idr_remove(&mem_cgroup_idr, memcg->id.id);
+ mem_cgroup_id_remove(memcg);
__mem_cgroup_free(memcg);
return NULL;
}
@@ -4245,6 +4251,7 @@ mem_cgroup_css_alloc(struct cgroup_subsy
return &memcg->css;
fail:
+ mem_cgroup_id_remove(memcg);
mem_cgroup_free(memcg);
return ERR_PTR(-ENOMEM);
}
_
next prev parent reply other threads:[~2018-07-26 23:25 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-12 14:52 [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure Kirill Tkhai
2018-04-13 8:55 ` Michal Hocko
2018-04-13 9:35 ` Kirill Tkhai
2018-04-13 11:02 ` Michal Hocko
2018-04-13 11:06 ` Kirill Tkhai
2018-04-13 11:20 ` Michal Hocko
2018-04-13 11:29 ` Kirill Tkhai
2018-04-13 11:38 ` Michal Hocko
2018-04-13 11:49 ` Kirill Tkhai
2018-04-13 11:54 ` Michal Hocko
2018-04-13 12:07 ` Kirill Tkhai
2018-04-13 12:14 ` Michal Hocko
2018-04-13 12:51 ` Michal Hocko
2018-07-26 23:25 ` Andrew Morton [this message]
2018-07-27 19:31 ` Johannes Weiner
2018-07-29 19:26 ` Vladimir Davydov
2018-07-30 15:31 ` Johannes Weiner
2018-07-31 23:39 ` Andrew Morton
2018-08-01 15:55 ` Johannes Weiner
2018-08-01 16:22 ` Vladimir Davydov
2018-08-02 8:03 ` Kirill Tkhai
2018-08-02 8:13 ` [PATCH] memcg: Add comment to mem_cgroup_css_online() Kirill Tkhai
2018-08-01 16:16 ` [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure Vladimir Davydov
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