Messages in this thread | | | Date | Thu, 11 Dec 2008 09:25:31 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [RFC][PATCH 1/6] memcg: fix pre_destory handler |
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On Wed, 10 Dec 2008 10:35:34 -0800 Paul Menage <menage@google.com> wrote:
> On Wed, Dec 10, 2008 at 3:29 AM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu@jp.fujitsu.com> wrote: > > > > (BTW, I don't like hierarchy-walk-by-small-locks approarch now because > > I'd like to implement scan-and-stop-continue routine. > > See how readdir() aginst /proc scans PID. It's very roboust against > > very temporal PIDs.) > > So you mean that you want to be able to sleep, and then contine > approximately where you left off, without keeping any kind of > reference count on the last cgroup that you touched? OK, so in that > case I agree that you would need some kind of hierarch > > > I tried similar patch and made it to use only one shared refcnt. > > (my previous patch...) > > A crucial difference is that your css_tryget() fails if the cgroups > framework is trying to remove the cgroup but might abort due to > another subsystem holding a reference, whereas mine spins and if the > rmdir is aborted it will return a refcount. > sure. > > > > We need rolling update of refcnts and rollback. Such code tends to make > > a hole (This was what my first patch did...). > > Can you clarify what you mean by "rolling update of refcnts"? > for(..i++) atomic_dec/inc( refcnt[i)
But my first version of this patch did above. I can write it again easily.
Thanks, -Kame
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