linux-kernel - [PATCH] memcg: Add comment to mem_cgroup_css

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <521f9e5f-c436-b388-fe83-4dc870bfb489@virtuozzo.com>
Date:   Thu, 2 Aug 2018 11:13:24 +0300
From:   Kirill Tkhai <ktkhai@...tuozzo.com>
To:     Vladimir Davydov <vdavydov.dev@...il.com>,
        Johannes Weiner <hannes@...xchg.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...nel.org>, cgroups@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [PATCH] memcg: Add comment to mem_cgroup_css_online()

Explain relationships between allocation and expanding.

Suggested-by: Vladimir Davydov <vdavydov.dev@...il.com>
Signed-off-by: Kirill Tkhai <ktkhai@...tuozzo.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;