From: Zhongkun He <hezhongkun.hzk@bytedance.com>
To: Michal Hocko <mhocko@suse.com>
Cc: corbet@lwn.net, akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
linux-doc@vger.kernel.org, wuyun.abel@bytedance.com
Subject: Re: [External] Re: [RFC] mm: add new syscall pidfd_set_mempolicy()
Date: Wed, 12 Oct 2022 19:22:21 +0800 [thread overview]
Message-ID: <a0421769-c2b9-d59a-0358-3cc84b2cb2bd@bytedance.com> (raw)
In-Reply-To: <Y0aCiYMQ4liL2azT@dhcp22.suse.cz>
>
> Yes, this will require some refactoring and one potential way is to make
> mpol ref counting unconditional. The conditional ref. counting has
> already caused issues in the past and the code is rather hard to follow
> anyway. I am not really sure this optimization is worth it.
>
> Another option would be to block the pidfd side of things on completion
> which would wake it up from the task_work context but I would rather
> explore the ref counting approach first and only if this is proven to be
> too expensive to go with hacks like this.
Hi Michal
The counting approach means executing mpol_get/put() when start/finish
using mempolicy,right? With the addition of lock add/dec on the hot
path, the performance may be degraded.
I'll try it to see its performance impact in detail.
Thanks.
next prev parent reply other threads:[~2022-10-12 11:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-10 9:48 Zhongkun He
2022-10-10 16:22 ` Frank van der Linden
2022-10-11 15:00 ` Michal Hocko
2022-10-11 17:22 ` Frank van der Linden
2022-10-11 19:29 ` Michal Hocko
2022-10-12 3:14 ` Abel Wu
2022-10-12 12:34 ` Vinicius Petrucci
2022-10-12 13:07 ` Michal Hocko
2022-10-12 13:23 ` Michal Hocko
2022-10-12 16:51 ` Frank van der Linden
2022-10-11 14:57 ` Michal Hocko
2022-10-12 7:55 ` [External] " Zhongkun He
2022-10-12 9:02 ` Michal Hocko
2022-10-12 11:22 ` Zhongkun He [this message]
2022-10-12 12:15 ` Michal Hocko
2022-10-13 10:44 ` Zhongkun He
2022-10-13 11:26 ` Michal Hocko
2022-10-13 12:50 ` Zhongkun He
2022-10-13 13:17 ` Michal Hocko
2022-10-13 13:42 ` Zhongkun He
2022-10-12 4:16 ` Bagas Sanjaya
2022-10-12 8:18 ` [External] " Zhongkun He
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=a0421769-c2b9-d59a-0358-3cc84b2cb2bd@bytedance.com \
--to=hezhongkun.hzk@bytedance.com \
--cc=akpm@linux-foundation.org \
--cc=corbet@lwn.net \
--cc=linux-api@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=wuyun.abel@bytedance.com \
/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