Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757421Ab3DOCuW (ORCPT ); Sun, 14 Apr 2013 22:50:22 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:25914 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753655Ab3DOCuQ (ORCPT ); Sun, 14 Apr 2013 22:50:16 -0400 Message-ID: <516B6AD8.4000807@huawei.com> Date: Mon, 15 Apr 2013 10:50:00 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: Tejun Heo CC: , , , , , , Subject: Re: [PATCHSET] cgroup, memcg: introduce sane_behavior mount option References: <1365808259-31073-1-git-send-email-tj@kernel.org> In-Reply-To: <1365808259-31073-1-git-send-email-tj@kernel.org> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.135.68.215] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2733 Lines: 63 On 2013/4/13 7:10, Tejun Heo wrote: > It's a sad fact that at this point various cgroup controllers are > carrying so many idiosyncrasies and pure insanities that it simply > isn't possible to reach any sort of sane consistent behavior while > staying compatible with what already has been exposed to userland. > > To make progress, those behaviors need to go but we can't simply drop > or change the crazies as those are directly visible to userland. This > patchset implements a mount option - sane_behavior - which turns on > new saner behaviors, so that we can keep providing the old behaviors > while and after transitioning to saner ones. > > As the behaviors which should be changed are still being determined > and then implemented, __DEVEL__ prefix is added to the mount option > and it triggers a warning message when used. > > The mount option changes the following behaviors after this patchset. > > * Mount options "noprefix" and "clone_children" are disallowed. Also, > cgroupfs file cgroup.clone_children is not created. > > * When mounting an existing superblock, mount options should match. > This is currently pretty crazy. If one mounts a cgroup, creates a > subdirectory, unmounts it and then mount it again with different > option, it looks like the new options are applied but they aren't. > > * Remount is disallowed. > > * memcg: .use_hierarchy is forced on and the cgroupfs file is not > created. > > and there are a lot more to come. Basically, when turned on, all > controllers should be ready to be mounted in the same hierarchy and > not get in the way unless specifically configured - making blk-throtl > hierarchical would need this to flip the meaning of limits, cpuset to > allow tasks to run by default in new cgroups and handle empty cpusets > in a way friendly to being co-mounted, and so on. > > This patchset contains the following four patches. > > 0001-cgroup-convert-cgroupfs_root-flag-bits-to-masks-and-.patch > 0002-move-cgroupfs_root-to-include-linux-cgroup.h.patch > 0003-cgroup-introduce-sane_behavior-mount-option.patch > 0004-memcg-force-use_hierarchy-if-sane_behavior.patch > > 0001-0002 are prep patches. It exposes cgroupfs_root in cgroup.h so > that flags can be tested with inline helpers. > > 0003 introduces sane_behavior mount option and implements behavior > changes in cgroup core proper. > > 0004 makes memcg .use_hierarchy changes. > Looks good to me! Acked-by: Li Zefan -- 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/