From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [PATCH] cgroup: fix to allow mounting a hierarchy by name Date: Thu, 29 Dec 2011 10:50:06 +0800 Message-ID: <4EFBD55E.5030106@cn.fujitsu.com> References: <4EF9291D.7030208@cn.fujitsu.com> <20111227163535.GA17712@google.com> <4EFAB2E2.4040008@cn.fujitsu.com> <20111228163631.GN17712@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20111228163631.GN17712-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo Cc: LKML , Cgroups Tejun Heo wrote: > Hello, Li. > > On Wed, Dec 28, 2011 at 02:10:42PM +0800, Li Zefan wrote: >> The "name" option was introduced along with the "none" option, so we >> can distinguish between different cgroup hierarchies which have no >> bound subsystems, like this: >> >> # mount -t cgroup -o none,name=hier1 xxx /cgroup1 >> # mount -t cgroup -o none,name=hier2 xxx /cgroup2 >> >> As the name is unique, we have this "mount by hierarchy name" feature. > > I could be missing something but does that add anything other than > naming convenience? > The name option is necessary, otherwise how can we mount hierarchies as shown in the above example? >> It looks reasonable, but I guess few people know this feature. We can >> live with it, as it only saves us some typing when mounting an existing >> hierarchy. On the other hand, removing this small feature can hardly >> result in code reduction. > > If it's a redundant feature which has been broken over a year without > anyone complaining, it really doesn't need to exist. It might not > save a lot of code but would save some WTH moments. > The redundant feature is mouting existing hierarchies by specifying name only, and the cleanup patch I sent has this feature removed in effect. kernel/cgroup.c | 15 +++++++-------- 1 files changed, 7 insertions(+), 8 deletions(-) This is why I'm not so keen to remove the feature. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751658Ab1L2Crx (ORCPT ); Wed, 28 Dec 2011 21:47:53 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:53357 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1750941Ab1L2Crv (ORCPT ); Wed, 28 Dec 2011 21:47:51 -0500 Message-ID: <4EFBD55E.5030106@cn.fujitsu.com> Date: Thu, 29 Dec 2011 10:50:06 +0800 From: Li Zefan User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc14 Thunderbird/3.1.4 MIME-Version: 1.0 To: Tejun Heo CC: LKML , Cgroups Subject: Re: [PATCH] cgroup: fix to allow mounting a hierarchy by name References: <4EF9291D.7030208@cn.fujitsu.com> <20111227163535.GA17712@google.com> <4EFAB2E2.4040008@cn.fujitsu.com> <20111228163631.GN17712@google.com> In-Reply-To: <20111228163631.GN17712@google.com> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-12-29 10:47:01, Serialize by Router on mailserver/fnst(Release 8.5.1FP4|July 25, 2010) at 2011-12-29 10:47:02, Serialize complete at 2011-12-29 10:47:02 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > Hello, Li. > > On Wed, Dec 28, 2011 at 02:10:42PM +0800, Li Zefan wrote: >> The "name" option was introduced along with the "none" option, so we >> can distinguish between different cgroup hierarchies which have no >> bound subsystems, like this: >> >> # mount -t cgroup -o none,name=hier1 xxx /cgroup1 >> # mount -t cgroup -o none,name=hier2 xxx /cgroup2 >> >> As the name is unique, we have this "mount by hierarchy name" feature. > > I could be missing something but does that add anything other than > naming convenience? > The name option is necessary, otherwise how can we mount hierarchies as shown in the above example? >> It looks reasonable, but I guess few people know this feature. We can >> live with it, as it only saves us some typing when mounting an existing >> hierarchy. On the other hand, removing this small feature can hardly >> result in code reduction. > > If it's a redundant feature which has been broken over a year without > anyone complaining, it really doesn't need to exist. It might not > save a lot of code but would save some WTH moments. > The redundant feature is mouting existing hierarchies by specifying name only, and the cleanup patch I sent has this feature removed in effect. kernel/cgroup.c | 15 +++++++-------- 1 files changed, 7 insertions(+), 8 deletions(-) This is why I'm not so keen to remove the feature.