From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: [PATCH 2/3] cgroup: make the default root invisible when it's umounted Date: Tue, 3 Jun 2014 12:05:22 +0800 Message-ID: <538D4982.10905@huawei.com> References: <538D4956.5050205@huawei.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <538D4956.5050205@huawei.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo Cc: LKML , Cgroups 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. Signed-off-by: Li Zefan --- kernel/cgroup.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f73fe48..dabc486 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1788,6 +1788,8 @@ static void cgroup_kill_sb(struct super_block *sb) } else { if (root != &cgrp_dfl_root) percpu_ref_kill(&root->cgrp.self.refcnt); + else + cgrp_dfl_root_visible = false; } kernfs_kill_sb(sb); -- 1.8.0.2