From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: [Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh Date: Fri, 22 Nov 2013 13:46:09 +0800 Message-ID: <528EEFA1.7020408@huawei.com> References: <527C9D9B.8090802@asianux.com> <20131120173549.GO28946@htj.dyndns.org> <528D6E19.4080100@gmail.com> <528D89AA.6080102@gmail.com> <551116969.38084288.1385021094494.JavaMail.root@redhat.com> <20131121152645.GB3352@htj.dyndns.org> <1639659702.38807133.1385075581222.JavaMail.root@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1639659702.38807133.1385075581222.JavaMail.root-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Jan Stancek Cc: Tejun Heo , Chen Gang , Garrett Cooper , gaowanlong-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, chris-8NJIiSa5LzA@public.gmane.org, mitani-Czb31pHLG9l3+QwDJ9on6Q@public.gmane.org, lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > ----- Original Message ----- >> From: "Tejun Heo" >> To: "Jan Stancek" >> Cc: "Chen Gang" , "Garrett Cooper" , gaowanlong-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, >> chris-8NJIiSa5LzA@public.gmane.org, mitani-Czb31pHLG9l3+QwDJ9on6Q@public.gmane.org, lizf-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org, "Li Zefan" , >> containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> Sent: Thursday, 21 November, 2013 4:26:45 PM >> Subject: Re: [Suggestion] kernel: cgroup: mount failure in LTP cgroup_regression_test.sh >> >> Hello, Jan. >> >> On Thu, Nov 21, 2013 at 03:04:54AM -0500, Jan Stancek wrote: >>> it looks like those 2 subsystems are already mounted by systemd, >>> each in different hierarchy: >>> >>>> cpuacct 4 35 1 >>>> freezer 5 4 1 >>> >>> from Documentation/cgroups/cgroups.txt: >>> "If an active hierarchy with exactly the same set of subsystems already >>> exists, it will be reused for the new mount. If no existing hierarchy >>> matches, and any of the requested subsystems are in use in an existing >>> hierarchy, the mount will fail with -EBUSY. Otherwise, a new hierarchy >>> is activated, associated with the requested subsystems." >> >> Ah, cgroup now requires that those recycled mounts to have matching >> options. This is an intended behavior change because previously we >> could end up with mounts which have actual options which differ from >> what was specified by mount, which can be misleading at the very >> least. > > I believe the test always respected this requirement. Problem we see > is because of initial state of the system. Test appears to expect > that it is able to mount cgroups freely, but they are already in use. > >> Would it be possible to update LTP accordingly? > > I'm not sure the test can do anything (other than not run at all). > > Other option is to setup system in a way where cgroups are not in use > prior to running this test, though this may not be possible with systemd. > I believe each test will do cleanup after it finishes (like umount cgroupfs). I guess the system already mounted cgroupfs after boot and each cgroup subsystem was mounted separately? And that leads to this issue.