Messages in this thread | | | Date | Fri, 27 Feb 2009 09:38:35 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH 1/2] cgroup allow subsys to set default mode of its own file |
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On Thu, 26 Feb 2009 16:28:11 -0800 Paul Menage <menage@google.com> wrote:
> On Thu, Feb 26, 2009 at 1:00 PM, Andrew Morton > <akpm@linux-foundation.org> wrote: > > On Wed, 25 Feb 2009 16:35:55 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > >> When I wrote tools for maintain cgroup, I can't find which file is > >> writable intarfece or not via cgroup file systems. (finally, I did > >> dirty approach.) > >> IMHO, showing "this file is read-only" in explicit way is useful > >> for user-land (tools). In other story, a file whose name sounds read-only > >> may have "trigger" operation and support reseting. In this case, > >> "writable" is informative. > > > > Well, we have compatibility issues here. If we make this change, and > > people write tools which depend upon that change then those tools might > > break when run upon older kernels. > > I don't think that's too big a deal - a write can always fail at the > whim of a cgroups subsystem, so this would just be a hint to a tool > that it shouldn't even bother trying to write to the file. It should > be able to handle a failure. > > But I don't see why we can't figure out the mode automatically based > on whether or not there's a write handler defined for the control > file. > That's because I wanted to allow -w------- or -w--w---- or some
Thanks, -Kame
> Paul >
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