From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Nick Piggin <npiggin@kernel.dk>,
Linus Torvalds <torvalds@linux-foundation.org>,
Chris Mason <chris.mason@oracle.com>,
Frank Rowand <frank.rowand@am.sony.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Mike Galbraith <efault@gmx.de>, Paul Turner <pjt@google.com>,
Jens Axboe <axboe@kernel.dk>, Yong Zhang <yong.zhang0@gmail.com>,
linux-kernel@vger.kernel.org,
Jeremy Fitzhardinge <jeremy@goop.org>,
Linux-Arch <linux-arch@vger.kernel.org>,
Jeff Garzik <jeff@garzik.org>, Tejun Heo <tj@kernel.org>
Subject: Re: [RFC][PATCH] spinlock: Kill spin_unlock_wait()
Date: Wed, 5 Jan 2011 20:26:34 +0100 [thread overview]
Message-ID: <20110105192634.GA30361@redhat.com> (raw)
In-Reply-To: <1294254867.2016.281.camel@laptop>
On 01/05, Peter Zijlstra wrote:
>
> On Tue, 2011-01-04 at 17:45 +1100, Nick Piggin wrote:
> > So I agree, taking it out the back and shooting it in the head would make
> > the world a better place.
>
> There appear to be only two callsites of said horror,
Not sure I understand why spin_unlock_wait() is really awful, but OK.
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -956,7 +956,8 @@ NORET_TYPE void do_exit(long code)
> * an exiting task cleaning up the robust pi futexes.
> */
> smp_mb();
> - raw_spin_unlock_wait(&tsk->pi_lock);
> + raw_spin_lock_irq(&tsk->pi_lock);
> + raw_spin_unlock_irq(&tsk->pi_lock);
then you can kill smp_mb() above.
Oleg.
next prev parent reply other threads:[~2011-01-05 19:34 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20101224122338.172750730@chello.nl>
[not found] ` <20101224123742.724459093@chello.nl>
[not found] ` <AANLkTikGBsh0-QTe9CA2gwDtwzpdMi+fbDsTEKiJAL0P@mail.gmail.com>
[not found] ` <1294054362.2016.74.camel@laptop>
[not found] ` <20110104064542.GF3402@amd>
2011-01-05 19:14 ` [RFC][PATCH] spinlock: Kill spin_unlock_wait() Peter Zijlstra
2011-01-05 19:26 ` Oleg Nesterov [this message]
2011-01-05 19:43 ` Linus Torvalds
2011-01-05 19:43 ` Linus Torvalds
2011-01-06 9:32 ` Peter Zijlstra
2011-01-06 10:38 ` Nick Piggin
2011-01-06 18:26 ` Peter Zijlstra
2011-01-07 21:01 ` Tejun Heo
2011-01-07 21:13 ` Jeff Garzik
2011-01-07 21:13 ` Jeff Garzik
2011-01-07 21:33 ` Tejun Heo
2011-01-07 21:33 ` Tejun Heo
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