Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753654AbaFCNBu (ORCPT ); Tue, 3 Jun 2014 09:01:50 -0400 Received: from mail-qg0-f52.google.com ([209.85.192.52]:63684 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751129AbaFCNBs (ORCPT ); Tue, 3 Jun 2014 09:01:48 -0400 Date: Tue, 3 Jun 2014 09:01:44 -0400 From: Tejun Heo To: Li Zefan Cc: LKML , Cgroups Subject: Re: [PATCH 2/3] cgroup: make the default root invisible when it's umounted Message-ID: <20140603130144.GB26210@htj.dyndns.org> References: <538D4956.5050205@huawei.com> <538D4982.10905@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <538D4982.10905@huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 03, 2014 at 12:05:22PM +0800, Li Zefan wrote: > Before this patch (in a fresh system): > > # cat /proc/$$/cgroup > # mount -t cgroup -o __DEVEL__sane_behavior xxx /cgroup > # umount /cgroup > # cat /proc/$$/cgroup > 0:cpuset,cpu,cpuacct,memory,devices,freezer,net_cls,blkio,perf_event,net_prio,hugetlb:/ > > After this patch (in a fresh system): > > # cat ... > # mount ... > # umount ... > # cat /proc/$$/cgroup > # > > You won't see the default root after it's umounted. Hmmmm... I intentionally left it visible tho. The only reason we gate its visibility is avoid disturbing userland which doesn't know about and won't use the unified hierarchy. If the userland starts making use of it, there's no reason to hide it again especially as that's consistent with how other hierarchies behave too - they keep showing up if they have lingering refs. Thanks. -- tejun -- 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/