From: Shakeel Butt <shakeelb@google.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
Mel Gorman <mgorman@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Yafang Shao <laoar.shao@gmail.com>, Linux MM <linux-mm@kvack.org>,
Cgroups <cgroups@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] memcg: expose root cgroup's memory.stat
Date: Fri, 15 May 2020 17:13:12 -0700 [thread overview]
Message-ID: <CALvZod7rCcs+-1mmu4w3wRpuZ=op6LE2y3sG1xA2ZrSNJOG-mw@mail.gmail.com> (raw)
In-Reply-To: <20200515180906.GA630613@cmpxchg.org>
On Fri, May 15, 2020 at 11:09 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Fri, May 15, 2020 at 10:49:22AM -0700, Shakeel Butt wrote:
> > On Fri, May 15, 2020 at 8:00 AM Roman Gushchin <guro@fb.com> wrote:
> > > On Fri, May 15, 2020 at 06:44:44AM -0700, Shakeel Butt wrote:
> > > > On Fri, May 15, 2020 at 6:24 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
> > > > > You're right. It should only bypass the page_counter, but still set
> > > > > page->mem_cgroup = root_mem_cgroup, just like user pages.
> > >
> > > What about kernel threads? We consider them belonging to the root memory
> > > cgroup. Should their memory consumption being considered in root-level stats?
> > >
> > > I'm not sure we really want it, but I guess we need to document how
> > > kernel threads are handled.
> >
> > What will be the cons of updating root-level stats for kthreads?
>
> Should kernel threads be doing GFP_ACCOUNT allocations without
> memalloc_use_memcg()? GFP_ACCOUNT implies that the memory consumption
> can be significant and should be attributed to userspace activity.
>
> If the kernel thread has no userspace entity to blame, it seems to
> imply the same thing as a !GFP_ACCOUNT allocation: shared public
> infrastructure, not interesting to account to any specific cgroup.
>
> I'm not sure if we have such allocations right now. But IMO we should
> not account anything from kthreads, or interrupts for that matter,
> /unless/ there is a specific active_memcg that was set by the kthread
> or the interrupt.
I totally agree with you but I think your response is about memory
charging in IRQ/kthread context, a topic of a parallel patch from
Zefan Li at [1].
Here we are discussing stats update for kthreads e.g. should we update
root memcg's MEMCG_KERNEL_STACK_KB stat when we allocate stack for
kernel threads?
[1] http://lkml.kernel.org/r/3a721f62-5a66-8bc5-247b-5c8b7c51c555@huawei.com
next prev parent reply other threads:[~2020-05-16 0:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 17:06 [PATCH] memcg: expose root cgroup's memory.stat Shakeel Butt
2020-05-08 21:44 ` Johannes Weiner
2020-05-09 14:06 ` Shakeel Butt
2020-05-09 14:43 ` Yafang Shao
2020-05-15 8:29 ` Michal Hocko
2020-05-15 13:24 ` Johannes Weiner
2020-05-15 13:44 ` Shakeel Butt
2020-05-15 15:00 ` Roman Gushchin
2020-05-15 17:49 ` Shakeel Butt
2020-05-15 18:09 ` Johannes Weiner
2020-05-16 0:13 ` Shakeel Butt [this message]
2020-05-15 18:09 ` Roman Gushchin
2020-05-16 0:06 ` Shakeel Butt
2020-05-16 1:42 ` Chris Down
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CALvZod7rCcs+-1mmu4w3wRpuZ=op6LE2y3sG1xA2ZrSNJOG-mw@mail.gmail.com' \
--to=shakeelb@google.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=guro@fb.com \
--cc=hannes@cmpxchg.org \
--cc=laoar.shao@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mhocko@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).