From: Tejun Heo <tj@kernel.org>
To: Valentin Schneider <vschneid@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Lai Jiangshan <jiangshanlai@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Frederic Weisbecker <frederic@kernel.org>,
Juri Lelli <juri.lelli@redhat.com>, Phil Auld <pauld@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v7 4/4] workqueue: Unbind kworkers before sending them to exit()
Date: Wed, 11 Jan 2023 06:55:46 -1000 [thread overview]
Message-ID: <Y77qEu1fQHMWr6F1@slm.duckdns.org> (raw)
In-Reply-To: <xhsmhv8ldck2a.mognet@vschneid.remote.csb>
On Wed, Jan 11, 2023 at 12:49:49PM +0000, Valentin Schneider wrote:
> While we're here, for my own education I was trying to figure out in what
> scenarios we can hit this manager-already-active condition. When sending
> out v6 I had convinced myself it could happen during failed
> initialization of a new unbound pool, but having another look at it now I'm
> not so sure anymore.
>
> The only scenario I can think of now is around maybe_create_worker()'s
> release of pool->lock, as that implies another worker can drain the
> pool->worklist and thus let pool->refcnt reach 0 while another worker is
> being the pool manager. Am I looking at the right thing?
To be frank, I'm not sure and can't remember why the code is like that off
the top of my head. It could well be that I was just habitually thinking
that MANAGER can be contended while in practice the scenario can never
happen in this particular case. I'll need to look harder at it but maybe we
can leave that to another day?
Thanks.
--
tejun
next prev parent reply other threads:[~2023-01-11 16:56 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-09 13:33 [PATCH v7 0/4] workqueue: destroy_worker() vs isolated CPUs Valentin Schneider
2023-01-09 13:33 ` [PATCH v7 1/4] workqueue: Protects wq_unbound_cpumask with wq_pool_attach_mutex Valentin Schneider
2023-01-09 13:33 ` [PATCH v7 2/4] workqueue: Factorize unbind/rebind_workers() logic Valentin Schneider
2023-01-09 13:33 ` [PATCH v7 3/4] workqueue: Convert the idle_timer to a timer + work_struct Valentin Schneider
2023-01-09 13:33 ` [PATCH v7 4/4] workqueue: Unbind kworkers before sending them to exit() Valentin Schneider
2023-01-10 20:28 ` Tejun Heo
2023-01-11 12:49 ` Valentin Schneider
2023-01-11 16:55 ` Tejun Heo [this message]
2023-01-11 17:18 ` Valentin Schneider
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=Y77qEu1fQHMWr6F1@slm.duckdns.org \
--to=tj@kernel.org \
--cc=frederic@kernel.org \
--cc=jiangshanlai@gmail.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mtosatti@redhat.com \
--cc=pauld@redhat.com \
--cc=peterz@infradead.org \
--cc=vschneid@redhat.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
all inboxes | Powered by JetHome®