From: Waiman Long <longman@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org, kernel-team@android.com,
Zefan Li <lizefan.x@bytedance.com>, Tejun Heo <tj@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org
Subject: Re: [PATCH 1/2] cpuset: Fix cpuset_cpus_allowed() to not filter offline CPUs
Date: Fri, 3 Feb 2023 10:35:13 -0500 [thread overview]
Message-ID: <26617070-e32b-cfc2-d741-0294d5aea0c3@redhat.com> (raw)
In-Reply-To: <Y90nn9NVkEhcZ6nq@hirez.programming.kicks-ass.net>
On 2/3/23 10:26, Peter Zijlstra wrote:
> On Fri, Feb 03, 2023 at 10:13:10AM -0500, Waiman Long wrote:
>
>> I think I know where the problem is. It is due to the fact the cpuset
>> hotplug code doesn't update cpumasks of the tasks in the top cpuset (root)
>> at all when there is a cpu offline or online event. It is probably because
>> for some of the tasks in the top cpuset, especially the percpu kthread,
>> changing their cpumasks can be catastrophic. The hotplug code does update
>> the cpumasks of the tasks that are not in the top cpuset. This problem is
>> irrespective of whether v1 or v2 is in use.
> I've been saying this exact thing for how many mails now?
My bad. The fact that sched_getaffinity() masks off the offline cpus
makes me thought incorrectly that tasks in the top cpuset were also
updated by the hotplug code. Further testing indicates this is the case.
Thanks,
Longman
next prev parent reply other threads:[~2023-02-03 15:36 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-31 22:17 [PATCH 0/2] Fix broken cpuset affinity handling on heterogeneous systems Will Deacon
2023-01-31 22:17 ` [PATCH 1/2] cpuset: Fix cpuset_cpus_allowed() to not filter offline CPUs Will Deacon
2023-02-01 4:14 ` Waiman Long
2023-02-01 9:14 ` Peter Zijlstra
2023-02-01 15:16 ` Waiman Long
2023-02-01 18:46 ` Waiman Long
2023-02-01 19:14 ` Waiman Long
2023-02-01 19:17 ` Waiman Long
2023-02-01 21:10 ` Peter Zijlstra
2023-02-02 3:34 ` Waiman Long
2023-02-03 11:50 ` Will Deacon
2023-02-03 15:13 ` Waiman Long
2023-02-03 15:26 ` Peter Zijlstra
2023-02-03 15:35 ` Waiman Long [this message]
2023-02-02 8:34 ` Peter Zijlstra
2023-02-02 16:06 ` Waiman Long
2023-02-02 19:42 ` Peter Zijlstra
2023-02-02 20:46 ` Waiman Long
2023-02-02 20:48 ` Tejun Heo
2023-02-02 20:53 ` Waiman Long
2023-02-02 21:05 ` Waiman Long
2023-02-02 21:50 ` Tejun Heo
2023-02-03 0:54 ` Waiman Long
2023-02-03 16:31 ` Will Deacon
2023-01-31 22:17 ` [PATCH 2/2] cpuset: Call set_cpus_allowed_ptr() with appropriate mask for task Will Deacon
2023-02-01 2:22 ` Waiman Long
2023-02-01 9:15 ` Peter Zijlstra
2023-02-01 15:03 ` Waiman Long
2023-02-01 9:27 ` Peter Zijlstra
2023-02-03 17:55 ` Waiman Long
2023-02-06 20:21 ` Tejun Heo
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=26617070-e32b-cfc2-d741-0294d5aea0c3@redhat.com \
--to=longman@redhat.com \
--cc=cgroups@vger.kernel.org \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan.x@bytedance.com \
--cc=peterz@infradead.org \
--cc=tj@kernel.org \
--cc=will@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
Powered by JetHome