Re: [PATCH] cgroups: handle failure of cgroup_populate_dir() at mount/remount

From: KAMEZAWA Hiroyuki
Date: Tue May 26 2009 - 21:35:54 EST


On Wed, 27 May 2009 09:07:31 +0800
Li Zefan <lizf@xxxxxxxxxxxxxx> wrote:

> Paul Menage wrote:
> > On Fri, May 22, 2009 at 1:25 AM, KAMEZAWA Hiroyuki
> > <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
> >> Hm, shouldn't we allow "noprefix" to be effective only agaisnt cpuset ?
> >> I think it's just for backward-compatibility of cpuset.
> >> (I don't like the option at all.)
> >
> > Yes, exposing the "noprefix" option externally was one of the mistakes
> > I made when developing cgroups.
> >
> > It seems to me really unlikely that anyone is using "noprefix" for
>
> And "noprefix" is not documented in cgroups.txt, so I guess not
> many people know this option. Even libcgroup doesn't handle it.
>
> > anything other than implicitly when mounting the "cpuset" filesystem.
> > So I'd be inclined to just forbid it if we're mounting more than just
> > the cpuset subsystem. A bit of a nasty abstraction violation, but it
> > makes more sense overall. The only problem is that someone *might* be
> > using it - do we have any way to determine how, and how big do they
> > have to be before we care?
> >
>
> I think we can never know..

How about this method ?

- add "noprefix" to "to-be-removed" list.
- add "WARNING: noprefix option will be removed in 2.6.32 (or 2.6.31)" now
- remove "noprefix" in 2.6.31-rc or later

Thanks,
-Kame





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