[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From ru...@us.ibm.com 2016-07-18 15:08 EDT--- . -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
sudo cat /proc//mountinfo -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From shg...@cn.ibm.com 2016-06-18 09:49 EDT--- (In reply to comment #77) > "LXC cases, like docker and KVM" - did you mean non-lxc cases? > > xenial by default should now be using libpam-cgfs, should not be using > cgmanager, and should not be creating cpusets. Thanks for the info. However what I cares is the docker/KVM case. For example, when I created docker on xenial 16.04, the container process will still be added into /sys/fs/cgroup/cpuset/docker; When creating KVM, the KVM process will be added into sub cpuset cgroup as well. As a result, the issue can still impact those tasks. For the above, is it already covered(on higher xenial version) or does it need more consideration? Regards, - Simon -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From shg...@cn.ibm.com 2016-06-17 06:01 EDT--- (In reply to comment #63) > > @Sqxm - thanks for that input. > > For what it's worth you should be able to use ppa:serge-hallyn/systemd in > xenial to get cpusets not created by default. Unfortunately I need to make > some more changes (in particular to use the systemd-created cgroups when > they exist) before pushing this to the archive. Serge, Have these fixes covered LXC cases, like docker and KVM? If I understand correctly, you mentioned 2 fixes: - one for cgmanager with libpam-cgm - another for systemd. Thanks, - Simon -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From bharata@in.ibm.com 2015-07-12 06:07 EDT--- *** Bug 127595 has been marked as a duplicate of this bug. *** -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2015-06-16 04:50 EDT--- Hi, An update on this: We are looking at solving this issue in either of the following two ways: 1. Have a config option where user specifies the controllers to mount. 2. Have the patch that mounts cgroups for containers in systemd-shim, rather than systemd. Regards Preeti U Murthy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1392176] Comment bridged from LTC Bugzilla
Quoting bugproxy (bugpr...@us.ibm.com): --- Comment From preeti.mur...@in.ibm.com 2015-04-20 03:20 EDT--- Hi, We want cgroups to be mounted *without* the cpuset controller. From your conversation I could make out the following: 1. LXC does not have a hard requirement on cpusets. But the challenge in not mounting cpusets would be to teach LXC to identify that all controllers may not be mounted when it requests for cgroups. 2. If LXC can identify this, when any container workload asks for cpusets, LXC must fail and ask the user to mount cpusets by himself. 3. But the concern is about workloads that expect cpusets to be mounted implicitly. If this is the case, then this is clearly not the way forward. Is it possible to survey the existing workloads to verify this? Implement the change and look for breakages :) I'm still not convinced that we don't want to make the change only for powerpc systemx - x86 systems AFAIK don't hotplug like drunken sailors. Because if there are no such workloads, mounting cgroups without cpusets is the simplest way to address the problem. Another approach is the right one, that being having a cgroup hotplug daemon, which listens on udev events for cpu hotplug operations and update the allowed cpus and mems mask. Such a daemon must be implemented by the service which mounts cgroups, which is systemd in this case ? This will take longer to implement ? It'll require lots of discussion. If it turns out that upstream is happy with the feature, it could actually happen very quickly. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2015-04-20 03:20 EDT--- Hi, We want cgroups to be mounted *without* the cpuset controller. From your conversation I could make out the following: 1. LXC does not have a hard requirement on cpusets. But the challenge in not mounting cpusets would be to teach LXC to identify that all controllers may not be mounted when it requests for cgroups. 2. If LXC can identify this, when any container workload asks for cpusets, LXC must fail and ask the user to mount cpusets by himself. 3. But the concern is about workloads that expect cpusets to be mounted implicitly. If this is the case, then this is clearly not the way forward. Is it possible to survey the existing workloads to verify this? Because if there are no such workloads, mounting cgroups without cpusets is the simplest way to address the problem. Another approach is the right one, that being having a cgroup hotplug daemon, which listens on udev events for cpu hotplug operations and update the allowed cpus and mems mask. Such a daemon must be implemented by the service which mounts cgroups, which is systemd in this case ? This will take longer to implement ? Regards Preeti U Murthy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From mainam...@in.ibm.com 2015-04-09 09:58 EDT--- *** Bug 121220 has been marked as a duplicate of this bug. *** -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2015-04-09 02:55 EDT--- (In reply to comment #36) But I'm a bit worried, doesn't not mounting cpuset mean that containers, for instance, wouldn't work so well? You just won't be able to lock containers to cpusets. That is, even if cgmanager doesn't mount the cpuset cgroup, if *anything* mounts it, processes in that cgroup tree will experience the underlying issue, no? Yes. And I still think that systemd is currently mounting it regardless of cgmanager. So ideally the effective_cpus thing would be fixed to work for non-unified hierarchies. Ok, so given the situation, I suggest the following: Fixing this in the kernel will be an ugly hack. Moreover, userspace must take care of updating cpusets after hotplug operations. Therefore I see two ways forward: 1. Can systemd/cgmanager (whoever is mounting cgroups) mount cpuset controllers under the unified hierarchy, while mounting the rest under the legacy hierarchy? Here is the suggestion from the community: https://lkml.org/lkml/2015/4/6/196. 2. Systemd/cgmanager must have a daemon listening to hotplug events. On hotplug, the parent cgroups cpuset must be percolated down to the children. This is a better solution because the situation where cpus are hotplugged in for the first time (i.e from the cpu_possible_mask to cpu_online_mask), will be handled too. Can either of the above be done in systemd/cgmanager ? Regards Preeti U Murthy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From ara...@us.ibm.com 2015-04-07 15:56 EDT--- (In reply to comment #33) Yes Nish, take a look at the full example: root@ubuntu1504:/sys/fs/cgroup/cpuset# cat cpuset.cpus ; cat user.slice/cpuset.cpus 0-7 0-7 root@ubuntu1504:/sys/fs/cgroup/cpuset# echo 0 /sys/devices/system/cpu/cpu7/online root@ubuntu1504:/sys/fs/cgroup/cpuset# cat cpuset.cpus ; cat user.slice/cpuset.cpus 0-6 0-6 root@ubuntu1504:/sys/fs/cgroup/cpuset# echo 1 /sys/devices/system/cpu/cpu7/online root@ubuntu1504:/sys/fs/cgroup/cpuset# cat cpuset.cpus ; cat user.slice/cpuset.cpus 0-7 0-6 root@ubuntu1504:/sys/fs/cgroup/cpuset# ps aux | grep cgmanager root 5761 0.0 0.0 5120 3072 pts/1S+ 10:35 0:00 grep --color=auto cgmanager root 28368 0.0 0.0 4288 3392 ?Ss 10:31 0:00 /sbin/cgmanager -m name=systemd -M cpuset I *think* you'd need to have cgmanager's configuration file be correct at boot-time, and have started your system fresh. The workaround provided by Serge is to simply not mount the cpuset cgroup. So if you have /sys/fs/cgroup/cpuset (or really, `mount | grep cpuset`, as you can mount it wherever you want) upon boot, then the workaround is not working. Perhaps something else is mounting cpuset. But I'm a bit worried, doesn't not mounting cpuset mean that containers, for instance, wouldn't work so well? That is, even if cgmanager doesn't mount the cpuset cgroup, if *anything* mounts it, processes in that cgroup tree will experience the underlying issue, no? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1392176] Comment bridged from LTC Bugzilla
But I'm a bit worried, doesn't not mounting cpuset mean that containers, for instance, wouldn't work so well? You just won't be able to lock containers to cpusets. That is, even if cgmanager doesn't mount the cpuset cgroup, if *anything* mounts it, processes in that cgroup tree will experience the underlying issue, no? Yes. And I still think that systemd is currently mounting it regardless of cgmanager. So ideally the effective_cpus thing would be fixed to work for non-unified hierarchies. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2015-04-06 09:26 EDT--- On the legacy hierarchy, cpuset.cpus changes with hotplug. It does not on the unified/default hierarchy. The issue arises because cpuset.cpus changes in the legacy hierarchy and the effective cpus is equivalent to it. Regards Preeti U Murthy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 1392176] Comment bridged from LTC Bugzilla
Does 15.04 ship with the legacy hierarchy on by default, I'm assuming it does to minimize regressions? Sort of annoying to have a cgmanager flag that only should apply if legacy is in-use? Legacy will be in use for a long time, because the unified hierarchy breaks a great deal of existing software. Had unified hierarchy tried harder to be backward compatible, its adoption would be much faster. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From ara...@us.ibm.com 2015-03-23 18:25 EDT--- (In reply to comment #19) Does 15.04 ship with the legacy hierarchy on by default, I'm assuming it does to minimize regressions? Sort of annoying to have a cgmanager flag that only should apply if legacy is in-use? Legacy will be in use for a long time, because the unified hierarchy breaks a great deal of existing software. Had unified hierarchy tried harder to be backward compatible, its adoption would be much faster. Yep, so I've noticed. I just wanted clarity on the upstream status -- as there won't be any attempt to fix the underlying issue upstream for legacy. I think you've answered my question(s) indirectly, though, thanks! -Nish -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From ara...@us.ibm.com 2015-03-23 17:37 EDT--- Making my own comment external: Preeti, is this fixed upstream with the default hierarchy and the effective_cpus file? be4c9dd7aee5ecf3e748da68c27b38bdca70d444 e2b9a3d7d8f4ab2f3491b8ed2ac6af692a2269b2 It seems like with the new default hierarchy upstream and the effective_cpus file, we now will be able to distinguish between configured cpuset and effective cpusets, which is the root cause of this bug, afaict. Does 15.04 ship with the legacy hierarchy on by default, I'm assuming it does to minimize regressions? Sort of annoying to have a cgmanager flag that only should apply if legacy is in-use? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2015-02-06 12:26 EDT--- Yes(In reply to comment #11) It seems that what you really want is for, when a cpu is on-lined, for all or some tasks to have that cpu automatically added to their cpuset? Would that suffice? Yes, for those tasks which had the offlined cpu in their cpusets before hotplug, the cpu should be added back to their respective cpusets when it comes online. Regards Preeti U Murthy -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1392176] Comment bridged from LTC Bugzilla
--- Comment From preeti.mur...@in.ibm.com 2014-12-19 02:40 EDT--- (In reply to comment #6) I'm definately open to making this more flexible. The queestion is how best to allow the configuration. We could add a /etc/cgmanager.conf, or we could do it through command line options specified in /etc/default/cgmanager Would you be able to give some background on why cgroups are mounted in the first place? This is so that we have some clarity on this front. I understand that it is done for LXC containers, but why so? So if you can make this cgroup mounting tunable, what would be the default? It would be best if cgroups are not mounted after boot up and the user explicitly asks for this if required. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1392176 Title: mounts cgroups unconditionally which causes undesired effects with cpu hotplug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cgmanager/+bug/1392176/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
