linux-kernel - Re: [External] Re: [PATCH v5] mm: memcontrol: Add the missing numa

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 16 Sep 2020 10:40:57 -0400
From:   Johannes Weiner <hannes@...xchg.org>
To:     Muchun Song <songmuchun@...edance.com>
Cc:     Tejun Heo <tj@...nel.org>, Zefan Li <lizefan@...wei.com>,
        Jonathan Corbet <corbet@....net>,
        Michal Hocko <mhocko@...nel.org>,
        Vladimir Davydov <vdavydov.dev@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Roman Gushchin <guro@...com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Cgroups <cgroups@...r.kernel.org>, linux-doc@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>,
        Linux Memory Management List <linux-mm@...ck.org>
Subject: Re: [External] Re: [PATCH v5] mm: memcontrol: Add the missing
 numa_stat interface for cgroup v2

On Wed, Sep 16, 2020 at 12:14:49PM +0800, Muchun Song wrote:
> On Wed, Sep 16, 2020 at 5:50 AM Johannes Weiner <hannes@...xchg.org> wrote:
> >
> > On Wed, Sep 16, 2020 at 01:18:01AM +0800, Muchun Song wrote:
> > > In the cgroup v1, we have a numa_stat interface. This is useful for
> > > providing visibility into the numa locality information within an
> > > memcg since the pages are allowed to be allocated from any physical
> > > node. One of the use cases is evaluating application performance by
> > > combining this information with the application's CPU allocation.
> > > But the cgroup v2 does not. So this patch adds the missing information.
> > >
> > > Signed-off-by: Muchun Song <songmuchun@...edance.com>
> > > Suggested-by: Shakeel Butt <shakeelb@...gle.com>
> > > Reviewed-by: Shakeel Butt <shakeelb@...gle.com>
> >
> > Yup, that would be useful information to have. Just a few comments on
> > the patch below:
> >
> > > @@ -1368,6 +1368,78 @@ PAGE_SIZE multiple when read back.
> > >               collapsing an existing range of pages. This counter is not
> > >               present when CONFIG_TRANSPARENT_HUGEPAGE is not set.
> > >
> > > +  memory.numa_stat
> > > +     A read-only flat-keyed file which exists on non-root cgroups.
> >
> > It's a nested key file, not flat.
> 
> This is just copied from memory.stat documentation.Is the memory.stat
> also a nested key file?

No, memory.stat is a different format. From higher up in the document:

  Flat keyed

	KEY0 VAL0\n
	KEY1 VAL1\n
	...

  Nested keyed

	KEY0 SUB_KEY0=VAL00 SUB_KEY1=VAL01...
	KEY1 SUB_KEY0=VAL10 SUB_KEY1=VAL11...
	...

> > Otherwise, this looks reasonable to me.
> 
> OK. Will do that.

Thanks!