From: Michal Hocko <mhocko@kernel.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Heinrich Schuchardt <xypron.glpk@gmx.de>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: threads-max observe limits
Date: Tue, 24 Sep 2019 10:48:54 +0200 [thread overview]
Message-ID: <20190924084854.GD23050@dhcp22.suse.cz> (raw)
In-Reply-To: <87mueuu2oz.fsf@x220.int.ebiederm.org>
On Mon 23-09-19 16:23:40, Eric W. Biederman wrote:
>
> Michal,
>
> Thinking about this I have a hunch about what changed. I think at some
> point we changed from 4k to 8k kernel stacks. So I suspect if your
> client is seeing a lower threads-max it is because the size of the
> kernel data structures increased.
This is indeed the case. Starting since 6538b8ea886e ("x86_64: expand
kernel stack to 16K") (3.16) we use THREAD_SIZE_ORDER = 2 and that
halved the auto-tuned value.
In the particular case
3.12
kernel.threads-max = 515561
4.4
kernel.threads-max = 200000
Neither of the two values is really insane on 32GB machine.
I am not sure we want/need to tune the max_thread value further. If
anything the tuning should be removed altogether if proven not useful in
general. But we definitely need a way to override this auto-tuning.
Thanks
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2019-09-24 8:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-17 10:03 threads-max observe limits Michal Hocko
2019-09-17 15:28 ` Heinrich Schuchardt
2019-09-17 15:38 ` Michal Hocko
2019-09-17 17:26 ` Eric W. Biederman
2019-09-18 7:15 ` Michal Hocko
2019-09-19 7:59 ` Michal Hocko
2019-09-19 19:38 ` Andrew Morton
2019-09-19 19:33 ` Eric W. Biederman
2019-09-22 6:58 ` Michal Hocko
2019-09-22 15:31 ` Heinrich Schuchardt
2019-09-22 21:40 ` Eric W. Biederman
2019-09-22 21:24 ` Eric W. Biederman
2019-09-23 8:08 ` Michal Hocko
2019-09-23 21:23 ` Eric W. Biederman
2019-09-24 8:48 ` Michal Hocko [this message]
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=20190924084854.GD23050@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@vger.kernel.org \
--cc=xypron.glpk@gmx.de \
/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