From: Michal Hocko <mhocko@kernel.org>
To: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: akpm@linux-foundation.org, 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: Fri, 13 Apr 2018 14:51:01 +0200 [thread overview]
Message-ID: <20180413125101.GO17484@dhcp22.suse.cz> (raw)
In-Reply-To: <20180413121433.GM17484@dhcp22.suse.cz>
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
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 8c2ed1c2b72c..ca7e981a8a1a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4351,6 +4351,14 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg)
{
int node;
+ /*
+ * We are trying to remove the idr key when the last memcg
+ * reference drops which can be sooner than when the last
+ * css reference is dropped to recycle ids faster.
+ */
+ if (memcg->id.id > 0)
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
+
for_each_node(node)
free_mem_cgroup_per_node_info(memcg, node);
free_percpu(memcg->stat_cpu);
@@ -4411,8 +4419,6 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
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_free(memcg);
return NULL;
}
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-04-13 12:51 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 [this message]
2018-07-26 23:25 ` Andrew Morton
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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