From: Oleg Nesterov <oleg@redhat•com>
To: Miroslav Benes <mbenes@suse•cz>
Cc: Petr Mladek <pmladek@suse•com>,
jpoimboe@redhat•com, jeyu@kernel•org, jikos@kernel•org,
lpechacek@suse•cz, pavel@ucw•cz, live-patching@vger•kernel.org,
linux-kernel@vger•kernel.org,
Michael Ellerman <mpe@ellerman•id.au>,
Thomas Gleixner <tglx@linutronix•de>,
Ingo Molnar <mingo@redhat•com>, "H. Peter Anvin" <hpa@zytor•com>,
Andy Lutomirski <luto@kernel•org>,
linuxppc-dev@lists•ozlabs.org, x86@kernel•org
Subject: Re: [PATCH v3 1/2] livepatch: send a fake signal to all blocking tasks
Date: Thu, 2 Nov 2017 15:08:53 +0100 [thread overview]
Message-ID: <20171102140853.GB23415@redhat.com> (raw)
In-Reply-To: <alpine.LSU.2.21.1711021128220.19544@san.suse.cz>
On 11/02, Miroslav Benes wrote:
>
> On Wed, 1 Nov 2017, Oleg Nesterov wrote:
>
> > Note also that wake_up_state(TASK_INTERRUPTIBLE) won't wakeup the TASK_IDLE
> > kthreads, and most of the kthreads which use TASK_INTERRUPTIBLE should use
> > TASK_IDLE today, because in most cases TASK_INTERRUPTIBLE was used to not
> > contribute to loadavg.
>
> Yes. Unfortunately, we have TASK_IDLE for more than two years now and
> nothing much has happened yet. TASK_IDLE is still used sporadically. I'd
> like to be on the safe side with livepatch
OK, as I said I won't argue,
> and given that
> TASK_INTERRUPTIBLE loops should be prepared for spurious wakeups by
> definition,
Not really when it comes to kthreads.
Once again, unless kthread does allow_signal() TASK_INTERRUPTIBLE does
not really differ from TASK_UNINTERRUPTIBLE except the latter contributes
to loadavg. And that is why TASK_INTERRUPTIBLE was commonly used instead
of TASK_UNINTERRUPTIBLE, so I do not think that TASK_INTERRUPTIBLE loops
are more ready in general than TASK_UNINTERRUPTIBLE.
Oleg.
next prev parent reply other threads:[~2017-11-02 14:08 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20171031114853.841-1-mbenes@suse.cz>
2017-10-31 11:48 ` [PATCH v3 1/2] livepatch: send a fake signal to all blocking tasks Miroslav Benes
2017-11-01 15:06 ` Miroslav Benes
2017-11-01 15:13 ` Petr Mladek
2017-11-01 16:43 ` Oleg Nesterov
2017-11-02 10:36 ` Miroslav Benes
2017-11-02 14:08 ` Oleg Nesterov [this message]
2017-11-02 13:09 ` Josh Poimboeuf
2017-11-03 8:02 ` Miroslav Benes
2017-11-03 12:57 ` Josh Poimboeuf
2017-11-02 13:32 ` Josh Poimboeuf
2017-11-03 8:06 ` Miroslav Benes
2017-11-06 11:08 ` Pavel Machek
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