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Re: [libvirt] [PATCH v1 0/6] disable cgroup cpuset



On Thu, Dec 13, 2012 at 12:21:29PM +0800, Osier Yang wrote:
> On 2012年11月07日 18:38, Hu Tao wrote:
> >The reason to disable cgroup cpuset by default is: currently,
> >sub-directories of cgroup cpuset won't be auto-updated if
> >cpu hot-plug happens. For example, if we now have 0-3,5-7 pcpus
> >online, the value of /sys/fs/cgroup/cpuset/libvirt/qemu/mydom/cpuset.cpus
> >is 0-3,5-7, then pcpu 4 is hot-plugged, but the value of cpuset.cpus
> >is still 0-3,5-7. This will cause a problem that we can't pin
> >to a hot-plugged pcpu
> 
> IMHO it's a kernel bug and should be fixed in kernel instead.

The problem was discussed before, see

http://www.redhat.com/archives/libvir-list/2012-September/msg00165.html
http://www.redhat.com/archives/libvir-list/2012-September/msg00221.html

> 
> >
> >Users can still enable cpuset by editing qemu.conf.
> 
> And per users can enable/disable the cpuset cgroup in
> qemu.conf, why do we need to disable it by default? On one
> hand, it has to be enabled again once the kernel bug is fixed;
> On the other hand, disabling it affects many functions,
> it's not deserved to disable it with the only problem
> (actually the libvirt pinning just behaves correctly, as
> the hotplug pCPU is not visible yet, the root cause is in
> kernel) on pinning from my p.o.v.
> 
> >
> >
> >Hu Tao (6):
> >   cgroup: Add a flag VIR_CGROUP_DISABLE_CPUSET
> >   create cgroup controllers for driver according to config
> >   create cgroup controllers for domain according to config
> >   create cgroup controllers for vcpu according to config
> >   create cgroup controllers for emulator according to config
> >   disable cgroup cpuset by default
> >
> >  src/lxc/lxc_cgroup.c      |  4 +--
> >  src/lxc/lxc_driver.c      | 22 ++++++------
> >  src/lxc/lxc_process.c     |  4 +--
> >  src/qemu/qemu.conf        |  2 +-
> >  src/qemu/qemu_cgroup.c    | 15 ++++----
> >  src/qemu/qemu_conf.c      |  1 -
> >  src/qemu/qemu_driver.c    | 92 +++++++++++++++++++++++++++++------------------
> >  src/qemu/qemu_hotplug.c   |  9 +++--
> >  src/qemu/qemu_migration.c |  2 +-
> >  src/util/cgroup.c         | 49 +++++++++++++++++++------
> >  src/util/cgroup.h         | 12 ++++---
> >  11 files changed, 136 insertions(+), 76 deletions(-)
> >


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