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From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
	peterz@infradead.org, "Toke Høiland-Jørgensen" <toke@redhat.com>,
	"Kalle Valo" <kvalo@kernel.org>,
	"Johannes Berg" <johannes@sipsolutions.net>
Subject: Re: [PATCH v2] signal: break out of wait loops on kthread_stop()
Date: Tue, 28 Jun 2022 17:59:11 +0200	[thread overview]
Message-ID: <YrslT9h0whngMIhw@zx2c4.com> (raw)
In-Reply-To: <877d51udc7.fsf@email.froward.int.ebiederm.org>

Hi Eric,

On Mon, Jun 27, 2022 at 02:16:08PM -0500, Eric W. Biederman wrote:
> Semantically this makes a lot of sense.
> 
> Bloating up signal_pending which is mainly called in non-kthread
> contexts is undesirable.

I guess I understand that concern, but does it really matter here? This
is called by code that waits anyway, so it's not like performance
matters at all, right?

> Instead could you modify kthread_stop to call set_notify_signal().
> 
> That is exactly what set_notify_signal is there for.  When you don't
> actually have a signal but you want to break out of an interruptible
> loop.  My last round of work in the area decoupled set_notify_signal
> from any other semantics.

This sounds like the best option here, if in fact it does work. I'll
send in a patch for that and we can see how it interacts with the other
work you're doing.

Jason

  reply	other threads:[~2022-06-28 15:59 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-27 12:00 [PATCH] signal: break out of wait loops on kthread_stop() Jason A. Donenfeld
2022-06-27 13:27 ` Peter Zijlstra
2022-06-27 14:54   ` Jason A. Donenfeld
2022-06-27 14:57     ` [PATCH v2] " Jason A. Donenfeld
2022-06-27 19:16       ` Eric W. Biederman
2022-06-28 15:59         ` Jason A. Donenfeld [this message]
2022-06-28 16:14           ` [PATCH v3] " Jason A. Donenfeld
2022-07-04 12:22             ` Jason A. Donenfeld
2022-07-11 17:53               ` Jason A. Donenfeld
2022-07-11 18:57                 ` Eric W. Biederman
2022-07-11 20:18                   ` Jason A. Donenfeld
2022-07-11 20:21                     ` [PATCH v4] " Jason A. Donenfeld
2022-07-11 22:05                       ` Eric W. Biederman
2022-07-11 23:21                         ` [PATCH v5] " Jason A. Donenfeld
2022-07-12  0:00                           ` Eric W. Biederman
2022-07-12  0:18                             ` Jason A. Donenfeld
2022-07-11 22:04                     ` [PATCH v3] " Eric W. Biederman

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