From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754169Ab3HEQBM (ORCPT ); Mon, 5 Aug 2013 12:01:12 -0400 Received: from cantor2.suse.de ([195.135.220.15]:60007 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753686Ab3HEQBL (ORCPT ); Mon, 5 Aug 2013 12:01:11 -0400 Date: Mon, 5 Aug 2013 18:01:07 +0200 From: Michal Hocko To: Tejun Heo Cc: lizefan@huawei.com, hannes@cmpxchg.org, bsingharora@gmail.com, kamezawa.hiroyu@jp.fujitsu.com, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCHSET cgroup/for-3.12] cgroup: make cgroup_event specific to memcg Message-ID: <20130805160107.GM10146@dhcp22.suse.cz> References: <1375632446-2581-1-git-send-email-tj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375632446-2581-1-git-send-email-tj@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 04-08-13 12:07:21, Tejun Heo wrote: > Hello, Hi Tejun, > Like many other things in cgroup, cgroup_event is way too flexible and > complex - it strives to provide completely flexible event monitoring > facility in cgroup proper which allows any number of users to monitor > custom events. This is overboard, to say the least, Could you be more specific about what is so "overboard" about this interface? I am not familiar with internals much, so I cannot judge the complexity part, but I thought that eventfd was intended for this kind of kernel->userspace notifications. > and I strongly think that cgroup should not any new usages of this > facility and preferably deprecate the existing usages if at all > possible. So you think that vmpressure, oom notification or thresholds are an abuse of this interface? What would you consider a reasonable replacement for those notifications? Or do you think that controller shouldn't be signaling any conditions to the userspace at all? [...] -- Michal Hocko SUSE Labs