From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>,
Alexey Dobriyan <adobriyan@gmail.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0
Date: Tue, 27 May 2008 10:06:11 -0700 [thread overview]
Message-ID: <20080527170611.GD14296@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.LFD.1.10.0805270908250.2958@woody.linux-foundation.org>
On Tue, May 27, 2008 at 09:11:33AM -0700, Linus Torvalds wrote:
> On Tue, 27 May 2008, Paul E. McKenney wrote:
> >
> > But this will only help until preemptible spinlocks arrive, right?
>
> I don't think we will ever have preemptible spinlocks.
>
> If you preempt spinlocks, you have serious issues with contention and
> priority inversion etc, and you basically need to turn them into sleeping
> mutexes. So now you also need to do interrupts as sleepable threads etc
> etc.
Indeed, all of these are required in that case.
> And it would break the existing non-preempt RCU usage anyway.
Yes, preemptable spinlocks cannot work without preemptable RCU.
> Yeah, maybe the RT people try to do that, but quite frankly, it is insane.
> Spinlocks are *different* from sleeping locks, for a damn good reason.
Well, I guess I never claimed to be sane...
Anyway, will look at a preemptable RCU that waits for preempt-disable
sections of code.
Thanx, Paul
next prev parent reply other threads:[~2008-05-27 17:06 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-26 18:41 Linux 2.6.26-rc4 Linus Torvalds
2008-05-26 21:24 ` Jesper Krogh
2008-05-26 21:42 ` Linus Torvalds
2008-05-27 0:25 ` Arjan van de Ven
2008-05-27 0:31 ` Arjan van de Ven
2008-05-27 5:43 ` David Woodhouse
2008-05-27 6:00 ` Arjan van de Ven
2008-05-27 6:24 ` David Woodhouse
2008-05-27 1:16 ` Carl-Daniel Hailfinger
2008-05-27 1:23 ` Carl-Daniel Hailfinger
2008-05-27 1:52 ` Abhijit Menon-Sen
2008-05-27 5:19 ` Jesper Krogh
2008-05-27 5:31 ` [MTD] [MAPS] ck804rom: fix driver_data in probe table David Woodhouse
2008-05-27 5:31 ` Linux 2.6.26-rc4 David Woodhouse
2008-05-27 10:35 ` Jeff Garzik
2008-05-27 10:53 ` Carl-Daniel Hailfinger
2008-05-27 10:54 ` Jeff Garzik
2008-05-27 10:58 ` Carl-Daniel Hailfinger
2008-05-27 5:23 ` 2.6.26-rc4: RIP find_pid_ns+0x6b/0xa0 Alexey Dobriyan
2008-05-27 9:06 ` Oleg Nesterov
2008-05-27 15:03 ` Linus Torvalds
2008-05-27 15:40 ` Paul E. McKenney
2008-05-27 16:11 ` Linus Torvalds
2008-05-27 17:06 ` Paul E. McKenney [this message]
2008-05-28 5:01 ` Paul E. McKenney
2008-05-28 7:26 ` Paul E. McKenney
2008-05-27 16:45 ` Oleg Nesterov
2008-05-27 17:37 ` Oleg Nesterov
2008-05-27 21:26 ` Alexey Dobriyan
2008-05-27 10:01 ` Linux 2.6.26-rc4 J.A. Magallón
2008-05-28 23:59 ` Bill Davidsen
[not found] ` <20080527124315.131b1343@Varda>
2008-05-28 20:10 ` Linus Torvalds
2008-05-28 20:10 ` Linus Torvalds
2008-05-28 20:17 ` Johannes Berg
2008-05-28 21:48 ` John W. Linville
2008-05-28 21:48 ` John W. Linville
2008-06-03 9:49 ` Jesper Krogh
2008-06-03 9:57 ` Al Viro
2008-06-03 10:04 ` Jesper Krogh
2008-06-03 10:13 ` Miklos Szeredi
2008-06-03 10:37 ` Miklos Szeredi
2008-06-03 10:48 ` Al Viro
2008-06-03 13:31 ` Ian Kent
2008-06-03 13:32 ` Ian Kent
2008-06-03 10:40 ` Al Viro
2008-06-03 10:45 ` Miklos Szeredi
2008-06-03 10:52 ` Al Viro
2008-06-03 13:27 ` Ian Kent
2008-06-03 15:01 ` Linus Torvalds
2008-06-03 16:07 ` Ian Kent
2008-06-03 16:35 ` Linus Torvalds
2008-06-03 16:41 ` Al Viro
2008-06-03 16:50 ` Al Viro
2008-06-03 17:28 ` Ian Kent
2008-06-03 17:41 ` Al Viro
2008-06-03 17:41 ` Ian Kent
2008-06-03 17:50 ` Al Viro
2008-06-03 17:49 ` Ian Kent
2008-06-03 16:59 ` Linus Torvalds
2008-06-03 17:30 ` Ian Kent
2008-06-03 17:13 ` Ian Kent
2008-06-03 17:30 ` Al Viro
2008-06-03 17:38 ` Ian Kent
2008-06-03 17:46 ` Jeff Moyer
2008-06-03 19:18 ` Al Viro
2008-06-03 19:53 ` Jeff Moyer
2008-06-03 23:00 ` Al Viro
2008-06-04 2:42 ` Ian Kent
2008-06-04 5:34 ` Miklos Szeredi
2008-06-04 5:41 ` Ian Kent
2008-06-10 4:57 ` Ian Kent
2008-06-10 6:28 ` Jesper Krogh
2008-06-10 6:40 ` Ian Kent
2008-06-10 9:09 ` Ian Kent
2008-06-12 3:03 ` Ian Kent
2008-06-12 7:02 ` Jesper Krogh
2008-06-12 11:21 ` Ian Kent
2008-06-12 11:19 ` Ian Kent
2008-06-04 1:36 ` Ian Kent
2008-06-05 7:31 ` Ian Kent
2008-06-05 21:29 ` Linus Torvalds
2008-06-05 21:34 ` Jesper Krogh
2008-06-06 2:39 ` Ian Kent
2008-06-05 22:30 ` Andrew Morton
2008-06-06 2:47 ` Ian Kent
2008-06-27 4:18 ` Ian Kent
2008-06-06 6:23 ` Jesper Krogh
2008-06-06 8:21 ` Ian Kent
2008-06-06 8:25 ` Ian Kent
2008-06-03 10:35 ` Al Viro
2008-06-04 17:51 ` Jesper Krogh
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