From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f200.google.com (mail-lj1-f200.google.com [209.85.208.200]) by kanga.kvack.org (Postfix) with ESMTP id 3EA286B0006 for ; Sun, 29 Jul 2018 15:26:27 -0400 (EDT) Received: by mail-lj1-f200.google.com with SMTP id u22-v6so1688026lji.9 for ; Sun, 29 Jul 2018 12:26:27 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id n12-v6sor1986061ljj.100.2018.07.29.12.26.25 for (Google Transport Security); Sun, 29 Jul 2018 12:26:25 -0700 (PDT) Date: Sun, 29 Jul 2018 22:26:21 +0300 From: Vladimir Davydov Subject: Re: [PATCH] memcg: Remove memcg_cgroup::id from IDR on mem_cgroup_css_alloc() failure Message-ID: <20180729192621.py4znecoinw5mqcp@esperanza> References: <20180413112036.GH17484@dhcp22.suse.cz> <6dbc33bb-f3d5-1a46-b454-13c6f5865fcd@virtuozzo.com> <20180413113855.GI17484@dhcp22.suse.cz> <8a81c801-35c8-767d-54b0-df9f1ca0abc0@virtuozzo.com> <20180413115454.GL17484@dhcp22.suse.cz> <20180413121433.GM17484@dhcp22.suse.cz> <20180413125101.GO17484@dhcp22.suse.cz> <20180726162512.6056b5d7c1d2a5fbff6ce214@linux-foundation.org> <20180727193134.GA10996@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180727193134.GA10996@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Michal Hocko , Kirill Tkhai , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Fri, Jul 27, 2018 at 03:31:34PM -0400, Johannes Weiner wrote: > That said, the lifetime of the root reference on the ID is the online > state, we put that in css_offline. Is there a reason we need to have > the ID ready and the memcg in the IDR before onlining it? I fail to see any reason for this in the code. > Can we do something like this and not mess with the alloc/free > sequence at all? I guess so, and this definitely looks better to me.