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From: Kirill Tkhai <ktkhai@virtuozzo.com>
To: Vladimir Davydov <vdavydov.dev@gmail.com>,
	Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@kernel.org>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH] memcg: Add comment to mem_cgroup_css_online()
Date: Thu, 2 Aug 2018 11:13:24 +0300	[thread overview]
Message-ID: <521f9e5f-c436-b388-fe83-4dc870bfb489@virtuozzo.com> (raw)
In-Reply-To: <7a836e47-f0a4-6802-9b90-cc473e5ab90b@virtuozzo.com>

Explain relationships between allocation and expanding.

Suggested-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
---
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d90993ef1d7d..34e5ff72ce87 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4703,6 +4703,11 @@ static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
 {
 	struct mem_cgroup *memcg = mem_cgroup_from_css(css);
 
+	/*
+	 * A memcg must be visible for memcg_expand_shrinker_maps()
+	 * by the time the maps are allocated. So, we allocate maps
+	 * here, when for_each_mem_cgroup() can't skip it.
+	 */
 	if (memcg_alloc_shrinker_maps(memcg)) {
 		mem_cgroup_id_remove(memcg);
 		return -ENOMEM;

  reply	other threads:[~2018-08-02  8:13 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
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                                         ` Kirill Tkhai [this message]
2018-08-01 16:16                                 ` Vladimir Davydov

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