From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>,
Michal Hocko <mhocko@kernel.org>,
Kirill Tkhai <ktkhai@virtuozzo.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: Tue, 31 Jul 2018 16:39:08 -0700 [thread overview]
Message-ID: <20180731163908.603d7a27c6534341e1afa724@linux-foundation.org> (raw)
In-Reply-To: <20180730153113.GB4567@cmpxchg.org>
On Mon, 30 Jul 2018 11:31:13 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:
> Subject: [PATCH] mm: memcontrol: simplify memcg idr allocation and error
> unwinding
>
> The memcg ID is allocated early in the multi-step memcg creation
> process, which needs 2-step ID allocation and IDR publishing, as well
> as two separate IDR cleanup/unwind sites on error.
>
> Defer the IDR allocation until the last second during onlining to
> eliminate all this complexity. There is no requirement to have the ID
> and IDR entry earlier than that. And the root reference to the ID is
> put in the offline path, so this matches nicely.
This patch isn't aware of Kirill's later "mm, memcg: assign memcg-aware
shrinkers bitmap to memcg", which altered mem_cgroup_css_online():
@@ -4356,6 +4470,11 @@ static int mem_cgroup_css_online(struct
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+ if (memcg_alloc_shrinker_maps(memcg)) {
+ mem_cgroup_id_remove(memcg);
+ return -ENOMEM;
+ }
+
/* Online state pins memcg ID, memcg ID pins CSS */
atomic_set(&memcg->id.ref, 1);
css_get(css);
next prev parent reply other threads:[~2018-07-31 23:39 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
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 [this message]
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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