[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20071024134404.GB82@tv-sign.ru>
Date: Wed, 24 Oct 2007 17:44:04 +0400
From: Oleg Nesterov <oleg@...sign.ru>
To: Rusty Russell <rusty@...tcorp.com.au>
Cc: ego@...ibm.com, Linus Torvalds <torvalds@...ux-foundation.org>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org,
Srivatsa Vaddagiri <vatsa@...ibm.com>,
Dipankar Sarma <dipankar@...ibm.com>,
Ingo Molnar <mingo@...e.hu>
Subject: Re: [RFC PATCH 4/5] Remove CPU_DEAD/CPU_UP_CANCELLED handling from workqueue.c
On 10/24, Rusty Russell wrote:
>
> On Wednesday 24 October 2007 15:37:16 Gautham R Shenoy wrote:
> > @@ -712,7 +712,7 @@ static void start_workqueue_thread(struc
> >
> > if (p != NULL) {
> > if (cpu >= 0)
> > - kthread_bind(p, cpu);
> > + set_cpus_allowed(p, cpumask_of_cpu(cpu));
> > wake_up_process(p);
> > }
>
> Hi Gautham!
>
> This works, although the change is unnecessary.
kthread_bind() changes ->cpu/->cpus_allowed without any locks.
Currently this is possible because nobody can wakeup the new thread
after wait_task_inactive() succeeds. With this patch this is not true
any longer, cwq->thread can sleep, for example, on cwq->more_work.
Oleg.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists