Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760132Ab2J2WA1 (ORCPT ); Mon, 29 Oct 2012 18:00:27 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33029 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933062Ab2J2WAY (ORCPT ); Mon, 29 Oct 2012 18:00:24 -0400 Date: Mon, 29 Oct 2012 15:00:22 -0700 From: Andrew Morton To: Glauber Costa Cc: Michal Hocko , , , , Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh Subject: Re: [PATCH v3 3/6] memcg: Simplify mem_cgroup_force_empty_list error handling Message-Id: <20121029150022.a595b866.akpm@linux-foundation.org> In-Reply-To: <508E8B95.406@parallels.com> References: <1351251453-6140-1-git-send-email-mhocko@suse.cz> <1351251453-6140-4-git-send-email-mhocko@suse.cz> <508E8B95.406@parallels.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1193 Lines: 23 On Mon, 29 Oct 2012 17:58:45 +0400 Glauber Costa wrote: > > + * move charges to its parent or the root cgroup if the group has no > > + * parent (aka use_hierarchy==0). > > + * Although this might fail (get_page_unless_zero, isolate_lru_page or > > + * mem_cgroup_move_account fails) the failure is always temporary and > > + * it signals a race with a page removal/uncharge or migration. In the > > + * first case the page is on the way out and it will vanish from the LRU > > + * on the next attempt and the call should be retried later. > > + * Isolation from the LRU fails only if page has been isolated from > > + * the LRU since we looked at it and that usually means either global > > + * reclaim or migration going on. The page will either get back to the > > + * LRU or vanish. > > I just wonder for how long can it go in the worst case? If the kernel is uniprocessor and the caller is SCHED_FIFO: ad infinitum! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/