From: Alan Stern <stern@rowland.harvard.edu>
To: Thomas Gleixner <tglx@timesys.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@osdl.org>,
john stultz <johnstul@us.ibm.com>, Ingo Molnar <mingo@elte.hu>,
David Miller <davem@davemloft.net>,
Arjan van de Ven <arjan@infradead.org>,
Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@suse.de>
Subject: Re: BUG: cpufreq notification broken
Date: Thu, 16 Nov 2006 16:56:35 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.0611161654270.2460-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <1163712994.10333.49.camel@localhost.localdomain>
On Thu, 16 Nov 2006, Thomas Gleixner wrote:
> On Thu, 2006-11-16 at 16:26 -0500, Alan Stern wrote:
> > On Thu, 16 Nov 2006, Thomas Gleixner wrote:
> >
> > > There is another issue with this SRCU change:
> > >
> > > The notification comes actually after the real change, which is bad. We
> > > try to make the TSC usable by backing it with pm_timer accross such
> > > states, but this behaviour breaks the safety code.
> >
> > I don't understand. Sending notifications is completely separate from
> > setting up the notifier chain's head. The patch you mentioned didn't
> > touch the code that sends the notifications.
>
> Yeah, my bad. It just uses rcu based locking, but its still synchronous.
>
> I have to dig deeper, why the change of the frequency happens _before_
> the notifier arrives.
There are supposed to be _two_ notifier calls: one before the frequency
change and one after. Check the callers of cpufreq_notify_transition().
Alan Stern
prev parent reply other threads:[~2006-11-16 21:56 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-16 20:00 BUG: cpufreq notification broken Thomas Gleixner
2006-11-16 20:15 ` [patch] cpufreq: mark cpufreq_tsc() as core_initcall_sync Ingo Molnar
2006-11-16 20:45 ` Thomas Gleixner
2006-11-16 21:47 ` Linus Torvalds
2006-11-16 22:03 ` Alan Stern
2006-11-16 22:21 ` Linus Torvalds
2006-11-17 3:06 ` Alan Stern
2006-11-17 6:51 ` Paul E. McKenney
2006-11-17 9:29 ` Jens Axboe
2006-11-17 18:39 ` Oleg Nesterov
2006-11-18 0:28 ` Paul E. McKenney
2006-11-18 16:15 ` Alan Stern
2006-11-18 17:14 ` Paul E. McKenney
2006-11-18 19:34 ` Oleg Nesterov
2006-11-19 21:26 ` Paul E. McKenney
2006-11-18 21:00 ` Alan Stern
2006-11-18 21:25 ` Oleg Nesterov
2006-11-18 22:13 ` Alan Stern
2006-11-18 22:46 ` Oleg Nesterov
2006-11-19 20:12 ` Alan Stern
2006-11-19 21:43 ` Paul E. McKenney
2006-11-20 17:19 ` Alan Stern
2006-11-20 17:58 ` Jens Axboe
2006-11-20 19:39 ` Alan Stern
2006-11-20 20:13 ` Jens Axboe
2006-11-20 21:39 ` Alan Stern
2006-11-21 7:39 ` Jens Axboe
2006-11-20 18:57 ` Oleg Nesterov
2006-11-20 20:01 ` Alan Stern
2006-11-20 20:51 ` Paul E. McKenney
2006-11-21 20:04 ` Oleg Nesterov
2006-11-21 20:54 ` Alan Stern
2006-11-21 22:07 ` Paul E. McKenney
2006-11-20 20:38 ` Paul E. McKenney
2006-11-21 16:44 ` Oleg Nesterov
2006-11-21 19:56 ` Paul E. McKenney
2006-11-21 20:26 ` Alan Stern
2006-11-21 23:03 ` Paul E. McKenney
2006-11-22 2:17 ` Alan Stern
2006-11-22 17:01 ` Paul E. McKenney
2006-11-26 22:25 ` Oleg Nesterov
2006-11-27 21:10 ` Alan Stern
2006-11-28 1:47 ` Paul E. McKenney
2006-11-20 19:17 ` Paul E. McKenney
2006-11-20 20:22 ` Alan Stern
2006-11-21 17:55 ` Paul E. McKenney
2006-11-21 17:56 ` Alan Stern
2006-11-21 19:13 ` Paul E. McKenney
2006-11-21 20:40 ` Alan Stern
2006-11-22 18:08 ` Paul E. McKenney
2006-11-21 21:01 ` Oleg Nesterov
2006-11-22 0:51 ` Paul E. McKenney
2006-11-18 18:46 ` Oleg Nesterov
2006-11-19 21:07 ` Paul E. McKenney
2006-11-20 7:15 ` Jens Axboe
2006-11-20 16:59 ` Paul E. McKenney
2006-11-20 17:55 ` Jens Axboe
2006-11-20 20:09 ` Paul E. McKenney
2006-11-20 20:21 ` Jens Axboe
2006-11-18 19:02 ` Oleg Nesterov
2006-11-19 21:23 ` Paul E. McKenney
2006-11-17 19:15 ` Paul E. McKenney
2006-11-17 19:27 ` Alan Stern
2006-11-18 0:38 ` Paul E. McKenney
2006-11-18 4:33 ` Alan Stern
2006-11-18 4:51 ` Andrew Morton
2006-11-18 5:57 ` Paul E. McKenney
2006-11-19 19:00 ` Oleg Nesterov
2006-11-19 20:21 ` Alan Stern
2006-11-19 20:55 ` Oleg Nesterov
2006-11-19 21:09 ` Alan Stern
2006-11-19 21:17 ` Oleg Nesterov
2006-11-19 21:54 ` Paul E. McKenney
2006-11-19 22:28 ` Oleg Nesterov
2006-11-20 5:47 ` Paul E. McKenney
2006-11-19 21:20 ` Paul E. McKenney
2006-11-19 21:50 ` Oleg Nesterov
2006-11-19 22:04 ` Paul E. McKenney
2006-11-23 14:59 ` Oleg Nesterov
2006-11-23 20:40 ` Paul E. McKenney
2006-11-23 21:34 ` Oleg Nesterov
2006-11-23 21:49 ` Oleg Nesterov
2006-11-27 4:33 ` Paul E. McKenney
2006-11-24 18:21 ` Oleg Nesterov
2006-11-24 20:04 ` Jens Axboe
2006-11-24 20:47 ` Alan Stern
2006-11-24 21:13 ` Oleg Nesterov
2006-11-25 3:24 ` Alan Stern
2006-11-25 17:14 ` Oleg Nesterov
2006-11-25 22:06 ` Alan Stern
2006-11-26 21:34 ` Oleg Nesterov
2006-11-27 5:02 ` Paul E. McKenney
2006-11-27 16:11 ` Oleg Nesterov
2006-11-27 16:56 ` Oleg Nesterov
2006-11-29 19:29 ` Paul E. McKenney
2006-11-29 20:16 ` Oleg Nesterov
2006-11-29 23:08 ` Paul E. McKenney
2006-11-30 0:01 ` Oleg Nesterov
2006-11-17 2:33 ` Paul E. McKenney
2006-11-16 20:52 ` Peter Zijlstra
2006-11-16 21:20 ` Andrew Morton
2006-11-16 21:27 ` Thomas Gleixner
2006-11-20 19:57 ` Linus Torvalds
2006-11-16 20:27 ` BUG: cpufreq notification broken Alan Stern
2006-11-16 21:09 ` Thomas Gleixner
2006-11-16 21:26 ` Alan Stern
2006-11-16 21:36 ` Thomas Gleixner
2006-11-16 21:56 ` Alan Stern [this message]
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