From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure Date: Fri, 13 Apr 2018 10:55:53 +0200 Message-ID: <20180413085553.GF17484@dhcp22.suse.cz> References: <152354470916.22460.14397070748001974638.stgit@localhost.localdomain> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <152354470916.22460.14397070748001974638.stgit@localhost.localdomain> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Kirill Tkhai 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 On Thu 12-04-18 17:52:04, Kirill Tkhai wrote: [...] > @@ -4471,6 +4477,7 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) > > return &memcg->css; > fail: > + mem_cgroup_id_remove(memcg); > mem_cgroup_free(memcg); > return ERR_PTR(-ENOMEM); > } The only path which jumps to fail: here (in the current mmotm tree) is error = memcg_online_kmem(memcg); if (error) goto fail; AFAICS and the only failure path in memcg_online_kmem memcg_id = memcg_alloc_cache_id(); if (memcg_id < 0) return memcg_id; I am not entirely clear on memcg_alloc_cache_id but it seems we do clean up properly. Or am I missing something? -- Michal Hocko SUSE Labs