From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id D4ECC6B0009 for ; Fri, 13 Apr 2018 04:55:56 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id t123so893224wmt.8 for ; Fri, 13 Apr 2018 01:55:56 -0700 (PDT) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id r29si1180374edi.39.2018.04.13.01.55.55 for (version=TLS1 cipher=AES128-SHA bits=128/128); Fri, 13 Apr 2018 01:55:55 -0700 (PDT) Date: Fri, 13 Apr 2018 10:55:53 +0200 From: Michal Hocko Subject: Re: [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure Message-ID: <20180413085553.GF17484@dhcp22.suse.cz> References: <152354470916.22460.14397070748001974638.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <152354470916.22460.14397070748001974638.stgit@localhost.localdomain> Sender: owner-linux-mm@kvack.org List-ID: 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