From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Shuah Khan <shuah@kernel.org>,
cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH-cgroup 1/4] workqueue: Add workqueue_unbound_exclude_cpumask() to exclude CPUs from wq_unbound_cpumask
Date: Mon, 23 Oct 2023 17:28:44 -1000 [thread overview]
Message-ID: <ZTc57JX2qZiXn3p4@mtj.duckdns.org> (raw)
In-Reply-To: <f8796057-e7f0-b589-783f-d11538aaafbf@redhat.com>
Hello,
On Wed, Oct 18, 2023 at 03:18:52PM -0400, Waiman Long wrote:
> I have a second thought after taking a further look at that. First of all,
> cpuset_allowed_mask isn't relevant here and the mask can certainly contain
> offline CPUs. So cpu_possible_mask is the proper fallback.
>
> With the current patch, wq_user_unbound_cpumask is set up initially as
> (HK_TYPE_WQ ∩ HK_TYPE_DOMAIN) house keeping mask and rewritten by any
> subsequent write to workqueue/cpumask sysfs file. So using
The current behavior is not something which is carefully planned. It's more
accidental than anything. If we can come up with a more intutive and
consistent behavior, that should be fine.
> wq_user_unbound_cpumask has the implied precedence of user-sysfs written
> mask, command line isolcpus or nohz_full option mask and cpu_possible_mask.
> I think just fall back to wq_user_unbound_cpumask if the operation fails
> should be enough.
But yeah, that sounds acceptable.
Thanks.
--
tejun
next prev parent reply other threads:[~2023-10-24 3:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-13 18:11 [PATCH-cgroup 0/4] cgroup/cpuset: Improve CPU isolation in isolated partitions Waiman Long
2023-10-13 18:11 ` [PATCH-cgroup 1/4] workqueue: Add workqueue_unbound_exclude_cpumask() to exclude CPUs from wq_unbound_cpumask Waiman Long
2023-10-18 9:24 ` Tejun Heo
2023-10-18 13:41 ` Waiman Long
2023-10-18 19:18 ` Waiman Long
2023-10-24 3:28 ` Tejun Heo [this message]
2023-10-25 18:47 ` Waiman Long
2023-10-13 18:11 ` [PATCH-cgroup 2/4] selftests/cgroup: Minor code cleanup and reorganization of test_cpuset_prs.sh Waiman Long
2023-10-13 18:11 ` [PATCH-cgroup 3/4] cgroup/cpuset: Keep track of CPUs in isolated partitions Waiman Long
2023-10-18 9:26 ` Tejun Heo
2023-10-18 13:30 ` Waiman Long
2023-10-18 18:08 ` Tejun Heo
2023-10-18 18:24 ` Waiman Long
2023-10-24 3:25 ` Tejun Heo
2023-10-25 18:46 ` Waiman Long
2023-10-13 18:11 ` [PATCH-cgroup 4/4] cgroup/cpuset: Take isolated CPUs out of workqueue unbound cpumask Waiman Long
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