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From: Thomas Gleixner <tglx@linutronix.de>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
	mingo@redhat.com, akpm@linux-foundation.org,
	peterz@infradead.org
Subject: Re: [PATCHSET] timer: clean up initializers and implement irqsafe timers
Date: Tue, 14 Aug 2012 10:32:06 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LFD.2.02.1208141031180.32033@ionos> (raw)
In-Reply-To: <20120813233520.GG25632@google.com>

On Mon, 13 Aug 2012, Tejun Heo wrote:
> Hello,
> 
> On Wed, Aug 08, 2012 at 11:10:24AM -0700, Tejun Heo wrote:
> > Timer internals are protected by irqsafe lock but the lock is
> > naturally dropped and irq enabled while a timer is executed.  This
> > makes dequeueing timer for execution and the actual execution
> > non-atomic against IRQs.  No matter what the timer function does, IRQs
> > can occur between timer dispatch and execution.  This means that an
> > IRQ handler could interrupt any timer in progress and it's impossible
> > for an IRQ handler to cancel and drain a timer.
> 
> If nobody objects, I'll route this through wq/for-3.7 together with
> "workqueue: use irqsafe timer in delayed_work" patchset.  If you
> object, please scream.

SCREAM!

I'll reply to the original posting later - still processing my
vacation backlog.

Thanks,

	tglx

  reply	other threads:[~2012-08-14  8:32 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-08 18:10 Tejun Heo
2012-08-08 18:10 ` [PATCH 1/4] timer: generalize timer->base flags handling Tejun Heo
2012-08-21 16:40   ` [tip:timers/core] timer: Generalize " tip-bot for Tejun Heo
2012-08-08 18:10 ` [PATCH 2/4] timer: relocate declarations of init_timer_on_stack_key() Tejun Heo
2012-08-21 16:41   ` [tip:timers/core] timer: Relocate " tip-bot for Tejun Heo
2012-08-08 18:10 ` [PATCH 3/4] timer: clean up timer initializers Tejun Heo
2012-08-21 16:42   ` [tip:timers/core] timer: Clean " tip-bot for Tejun Heo
2012-08-08 18:10 ` [PATCH 4/4] timer: implement TIMER_IRQSAFE Tejun Heo
2012-08-21 16:43   ` [tip:timers/core] timer: Implement TIMER_IRQSAFE tip-bot for Tejun Heo
2012-08-21 19:26     ` Tejun Heo
2012-08-08 18:13 ` $SUBJ should have been "[PATCHSET] timer: clean up initializers and implement irqsafe timers" Tejun Heo
2012-08-13 23:35 ` [PATCHSET] timer: clean up initializers and implement irqsafe timers Tejun Heo
2012-08-14  8:32   ` Thomas Gleixner [this message]
2012-08-14 19:16   ` Thomas Gleixner
2012-08-14 19:22     ` Tejun Heo
2012-08-14 21:03       ` Thomas Gleixner
2012-08-14 21:56         ` Tejun Heo
2012-08-14 22:45           ` Thomas Gleixner
2012-08-14 23:01             ` Tejun Heo
2012-08-14 23:33               ` Thomas Gleixner
2012-08-15  0:18                 ` Tejun Heo
2012-08-15 10:58                   ` Peter Zijlstra
2012-08-16 19:36                     ` Tejun Heo
2012-08-14 18:55 ` Thomas Gleixner
2012-08-14 19:15   ` Tejun Heo
2012-08-14 20:43     ` Thomas Gleixner
2012-08-14 21:40       ` Tejun Heo
2012-08-14 23:12         ` Thomas Gleixner
2012-08-14 23:27           ` Tejun Heo
2012-08-14 23:46             ` Thomas Gleixner
2012-08-14 23:52               ` Tejun Heo

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