From: Tejun Heo <tj@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Suren Baghdasaryan <surenb@google.com>,
Matthew Wilcox <willy@infradead.org>,
Christoph Lameter <cl@linux.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Namhyung Kim <namhyung@google.com>,
linux-mm@kvack.org
Subject: Re: MM global locks as core counts quadruple
Date: Fri, 21 Jun 2024 09:10:02 -1000 [thread overview]
Message-ID: <ZnXQCrb36nfNfkwk@slm.duckdns.org> (raw)
In-Reply-To: <07e7d078-0c9d-6a1f-1ab5-295f86974b72@google.com>
Hello,
On Thu, Jun 20, 2024 at 05:35:45PM -0700, David Rientjes wrote:
> As core counts are rapidly expanding over the next four years, Namhyung
> and I were looking at global locks that we're already seeing high
> contention on even today.
>
> Some of these are not MM specific:
> - cgroup_mutex
Our machines are getting bigger but we aren't creating and destroying
cgroups frequently enough for this to matter. But yeah, I can see how this
can be a problem.
> - cgroup_threadgroup_rwsem
This one shouldn't matter at all in setups where new cgroups are populated
with CLONE_INTO_CGROUP and not migrated further. The lock isn't grabbed in
such usage pattern, which should be the vast majority already, I think. Are
you guys migrating tasks a lot or not using CLONE_INTO_CGROUP?
Thanks.
--
tejun
next prev parent reply other threads:[~2024-06-21 19:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-21 0:35 David Rientjes
2024-06-21 2:01 ` Matthew Wilcox
2024-06-21 2:46 ` Yafang Shao
2024-06-21 2:54 ` Matthew Wilcox
2024-06-26 19:38 ` Karim Manaouil
2024-06-27 5:36 ` Christoph Lameter (Ampere)
2024-06-21 19:10 ` Tejun Heo [this message]
2024-06-21 21:37 ` Namhyung Kim
2024-06-23 17:59 ` Tejun Heo
2024-06-24 21:44 ` David Rientjes
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=ZnXQCrb36nfNfkwk@slm.duckdns.org \
--to=tj@kernel.org \
--cc=Liam.Howlett@oracle.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=dave@stgolabs.net \
--cc=hannes@cmpxchg.org \
--cc=linux-mm@kvack.org \
--cc=namhyung@google.com \
--cc=paulmck@kernel.org \
--cc=rientjes@google.com \
--cc=surenb@google.com \
--cc=willy@infradead.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