From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx180.postini.com [74.125.245.180]) by kanga.kvack.org (Postfix) with SMTP id 35E996B0069 for ; Mon, 29 Oct 2012 18:00:24 -0400 (EDT) Date: Mon, 29 Oct 2012 15:00:22 -0700 From: Andrew Morton 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Glauber Costa Cc: Michal Hocko , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Li Zefan , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org