Re: [PATCH] [23/31] HWPOISON: add memory cgroup filter

From: KAMEZAWA Hiroyuki
Date: Wed Dec 09 2009 - 18:59:51 EST


On Wed, 9 Dec 2009 12:47:27 -0800
Paul Menage <menage@xxxxxxxxxx> wrote:

> On Tue, Dec 8, 2009 at 1:16 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> >
> > The hwpoison test suite need to inject hwpoison to a collection of
> > selected task pages, and must not touch pages not owned by them and
> > thus kill important system processes such as init. (But it's OK to
> > mis-hwpoison free/unowned pages as well as shared clean pages.
> > Mis-hwpoison of shared dirty pages will kill all tasks, so the test
> > suite will target all or non of such tasks in the first place.)
>
> While the functionality sounds useful, the interface (passing an inode
> number) feels a bit ugly to me. Also, if that group is deleted and a
> new cgroup created, you could end up reusing the inode number.
>
I agree.

> How about an approach where you write either the cgroup path (relative
> to the memcg mount) or an fd open on the desired cgroup? Then you
> could store a (counted) css reference rather than an inode number,
> which would make the filter function cleaner too, since it would just
> need to compare css objects.
>
Sounds reasonable.

Thanks,
-Kame


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