[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
** Changed in: libcgroup (Ubuntu) Assignee: Jon Bernard (jbernard) => (unassigned) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libcgroup/+bug/693594/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
> You're absolutely right, I will allocate time this week to put together > a new upstream release. > > Serge, would have have time to help me test and provide feedback? I will be out the remainder of this week. I can test it next week though. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libcgroup/+bug/693594/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
You're absolutely right, I will allocate time this week to put together a new upstream release. Serge, would have have time to help me test and provide feedback? Jon -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libcgroup/+bug/693594/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
Re: [Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Jon,
if you could do these soon in the Debian package, I think we should
still be able to get it into precise.
Rioting_Pacifst,
note that we generally recommend using cgroup-lite when possible.
Quoting Rioting_Pacifst (693...@bugs.launchpad.net):
> This bug has quite a few nasty symptoms (breaks suspend on SMP machines,
> etc) and I guess cgroups are going to get more popular as people try the
> "superpatch" so could we get one of the following into 12.04 please:
>
> 1)do not move all tasks into a default cgroup
> comment CREATE_DEFAULT=yes out and uncomment CREATE_DEFAULT=no in
> /etc/default/cgconfig
>
> 2)putting the following in /etc/cgconfig.conf
> group sysdefault {
> cpu {
> cpu.rt_runtime_us = 95;
> }
> }
>
> 3) Add a rule so that [kthreadd] is never put in the default group
>
> 4) Changing startup script to not move ktreadadd
>
> I think creating a superflous default group is stupid anyway so the
> first fix is by far the best.
>
> Upstream have also release 0.38 but nothing in the changelog seems
> relevant.
>
> --
> You received this bug notification because you are subscribed to
> libcgroup in Ubuntu.
> https://bugs.launchpad.net/bugs/693594
>
> Title:
> cgroup-bin should not move kthreadd into a default cgroup
>
> Status in “libcgroup” package in Ubuntu:
> Confirmed
>
> Bug description:
> Steps to reproduce:
> 1. Install cgroup-bin from universe on a stock Lucid machine (I've only
> tested amd64, but I suspect it shouldn't matter)
> 2. Load an arbitrary module (e.g. modprobe rds)
> 3. Unload the module loaded in (2) (e.g. rmmod rds)
>
> The 'rmmod' process will hang unkillably in the kernel.
>
> Here's an example `dmesg` output from the hung-task watchdog for
> rmmod:
>
> INFO: task rmmod:1608 blocked for more than 120 seconds.
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> rmmod D 0 1608 1440 0x
> 880014245c78 0082 00015bc0 00015bc0
> 880014804890 880014245fd8 00015bc0 8800148044d0
> 00015bc0 880014245fd8 00015bc0 880014804890
> Call Trace:
> [] schedule_timeout+0x22d/0x300
> [] ? rb_erase+0xd6/0x160
> [] ? __dequeue_entity+0x30/0x50
> [] wait_for_common+0xdb/0x180
> [] ? default_wake_function+0x0/0x20
> [] wait_for_completion+0x1d/0x20
> [] flush_cpu_workqueue+0x65/0xa0
> [] ? wq_barrier_func+0x0/0x20
> [] flush_workqueue+0x54/0x80
> [] __stop_machine+0xf4/0x120
> [] ? __try_stop_module+0x0/0x50
> [] stop_machine+0x3e/0x60
> [] ? find_module+0x34/0x70
> [] sys_delete_module+0x17e/0x270
> [] system_call_fastpath+0x16/0x1b
>
> The process is waiting on kstop/0 to wake up and service the stop_cpu
> workqueue work item that it has queued. kstop/0 is marked as
> TASK_RUNNABLE, but doesn't appear to ever be getting scheduled:
>
> $ ps -f 1609
> UIDPID PPID C STIME TTY STAT TIME CMD
> root 1609 2 0 14:47 ?R 0:00 [kstop/0]
>
> $ cat /proc/1609/stack
> [] worker_thread+0xda/0x110
> [] kthread+0x96/0xa0
> [] child_rip+0xa/0x20
> [] 0x
>
> I tracked this behavior down and reported it to the upstream kernel,
> but they say it's not a bug and that it's libcgroup's fault for moving
> kthreadd into a cgroup without RT privs:
> https://lkml.org/lkml/2011/1/5/53
>
> To manage notifications about this bug go to:
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cgroup-bin should not move kthreadd into a default cgroup
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[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
This bug has quite a few nasty symptoms (breaks suspend on SMP machines,
etc) and I guess cgroups are going to get more popular as people try the
"superpatch" so could we get one of the following into 12.04 please:
1)do not move all tasks into a default cgroup
comment CREATE_DEFAULT=yes out and uncomment CREATE_DEFAULT=no in
/etc/default/cgconfig
2)putting the following in /etc/cgconfig.conf
group sysdefault {
cpu {
cpu.rt_runtime_us = 95;
}
}
3) Add a rule so that [kthreadd] is never put in the default group
4) Changing startup script to not move ktreadadd
I think creating a superflous default group is stupid anyway so the
first fix is by far the best.
Upstream have also release 0.38 but nothing in the changelog seems
relevant.
--
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https://bugs.launchpad.net/bugs/693594
Title:
cgroup-bin should not move kthreadd into a default cgroup
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[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
a related issue with moving kernel threads is that one of them also breaks suspend :] it was fun to figure out! -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libcgroup/+bug/693594/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
This problem also happens in lucid (which is supposed to be an LTS release). Please fix this ASAP -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libcgroup/+bug/693594/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Hi, the core of this bug appears to be fixed in natty's newest libcgroup version (0.37.1-1ubuntu2). It no longer moves tasks into a default cgroup. I'm undecided as to whether to call that fixing this bug. I assume that changing the config files to set a default cgroup other than / will still cause kthreadd to be moved. I am assigning this to jbernard to get his opinion. If you think this bug should be called 'fix released', please let me know. Otherwise, if you have a good idea how to trivially stop kernel threads like kthreadd from being moved and want to do it, great. Finally, if you think it should be 'properly' fixed but prefer for me to do it, please reassign it to me. ** Changed in: libcgroup (Ubuntu) Assignee: (unassigned) => Jon Bernard (jbernard) -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
** Changed in: libcgroup (Ubuntu) Status: New => Confirmed ** Changed in: libcgroup (Ubuntu) Importance: Undecided => High -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Ok, I tried it one my little Lucid@virtualbox (1 CPU & 512MB defined) and well, it works. Just put a "echo 95 > /cgroups/cpu/sysdefault/cpu.rt_runtime_us" into "/etc/rc.local" and it is possible to load and unload kernel modules. Since I don't know how this works against cgroup at all, I would say this is a workaround not more. The problem itself has to be fixed in Lucid and Maverick, since issue doesn't happen there due to a lucky configuration circumstance ... But cgroup still work, I can see/feel it on my very thin equipped virtual Lucid, there some builds running in background, as write this and doing several other things. This was not possible in the installation. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
> "rt_runtime_us" is a adjustable value rather than a boolean, right? Right. In particular, it is the number of microseconds out of every second that a process scheduled with realtime priority is allowed to run for if it doesn't voluntarily yield the CPU, or something like that. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Hey, thx for the reply. Since I also ran in the problem on a VDR. In case of failure, VDR is covered by a watchdog, which tries do unload DVB modules. with cgroup- bin on Lucid, this ends in stop application, since rmmod does never come back. In the meantime I'm strongly interested in a workaround, because cgroups does give me some benefit, which I could only find if I replace my single core against a dual core CPU. So, "rt_runtime_us" is a adjustable value rather than a boolean, right? So, I'll try to echo the the value "95" with "/etc/rc.local" as a workaround on a test machine, to see if this works. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Yes, enabling real-time scheduling for sysdefault would also fix this. Although you probably want something like rt_runtime_us = 95, which is the default without any cgroups. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 693594] Re: cgroup-bin should not move kthreadd into a default cgroup
Would it make sense to enable the real time scheduler for the [sys]default process group [rt_runtime_us = 1]? At least as a kind of workaround ... ? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/693594 Title: cgroup-bin should not move kthreadd into a default cgroup -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
