[PATCH v4 0/4] cgroups: support for module-loadable subsystems
kamezawa.hiroyu at jp.fujitsu.com
Wed Jan 6 23:16:27 PST 2010
On Thu, 07 Jan 2010 14:42:19 +0800
Li Zefan <lizf at cn.fujitsu.com> wrote:
> KAMEZAWA Hiroyuki wrote:
> > On Wed, 6 Jan 2010 20:26:06 -0500
> > Ben Blum <bblum at andrew.cmu.edu> wrote:
> >> On Wed, Jan 06, 2010 at 04:04:14PM -0800, Andrew Morton wrote:
> >>> On Thu, 31 Dec 2009 00:10:50 -0500
> >>> Ben Blum <bblum at andrew.cmu.edu> wrote:
> >>>> This patch series implements support for building, loading, and
> >>>> unloading subsystems as modules, both within and outside the kernel
> >>>> source tree. It provides an interface cgroup_load_subsys() and
> >>>> cgroup_unload_subsys() which modular subsystems can use to register and
> >>>> depart during runtime. The net_cls classifier subsystem serves as the
> >>>> example for a subsystem which can be converted into a module using these
> >>>> changes.
> >>> What is the value in this? What are the usage scenarios? Why does the
> >>> benefit of this change exceed the cost/risk/etc of merging it?
> >> As discussed in the first posting of these patches, this provides the
> >> ability for arbitrary subsystems to be used with cgroups.. cls_cgroup
> >> would have already been a module except for a lack of support from
> >> cgroups, and the change also allows other module-loadable classifiers
> >> to add subsystems of their own.
> > Hmm, do you have your own module in plan ?
> Maybe the new blkio_cgroup can also be made module-able.
Hmm, I read the patch slightly. I'm not enough expert to review this patch..
I requst following as TODO.
(No objection to the direction/patch.)
1. Add documentation about load/unlod module.
It seems module unloading will not succuess while subsystem is mounted.
2. Making this to be reasonable value.
#define CGROUP_SUBSYS_COUNT (BITS_PER_BYTE*sizeof(unsigned long))
I can't find why.
3. show whehter a subsys is a loadable module or not via /proc/cgroups
4. how to test ? load/unload NET_CLS is enough ?
Last one is question.
5. Is following path is safe ?
get template including pointer
use template to build new css_set.
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