Messages in this thread | | | Date | Thu, 15 Jul 2010 09:00:48 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 00/11] blkiocg async support |
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On Wed, 14 Jul 2010 10:29:19 -0400 Vivek Goyal <vgoyal@redhat.com> wrote: > > > > Cgroup's feature as mounting several subsystems at a mount point at once > > is very useful in many case. > > I agree that it is useful but if some controllers are not supporting > hierarchy, it just adds to more confusion. And later when hierarchy > support comes in, there will be additional issue of keeping this file > "use_hierarchy" like memory controller. > > So at this point of time , I am not too inclined towards allowing hierarchical > cgroup creation but treating them as flat in CFQ. I think it adds to the > confusion and user space should handle this situation. >
Hmm.
Could you fix error code in create blkio cgroup ? It returns -EINVAL now. IIUC, mkdir(2) doesn't return -EINVAL as error code (from man.) Then, it's very confusing. I think -EPERM or -ENOMEM will be much better.
Anyway, I need to see source code of blk-cgroup.c to know why libvirt fails to create cgroup. Where is the user-visible information (in RHEL or Fedora) about "you can't use blkio-cgroup via libvirt or libcgroup" ?
Thanks, -Kame
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