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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: David Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org, wli@holomorphy.com,
	sparclinux@vger.kernel.org, manfred@colorfullife.com,
	akpm@linux-foundation.org
Subject: Re: [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs
Date: Tue, 9 Sep 2008 07:54:53 -0700	[thread overview]
Message-ID: <20080909145453.GA6711@linux.vnet.ibm.com> (raw)
In-Reply-To: <20080908.171708.43575256.davem@davemloft.net>

On Mon, Sep 08, 2008 at 05:17:08PM -0700, David Miller wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> Date: Wed, 3 Sep 2008 08:42:17 -0700
> > o	Timer irqs.  Not sure what happens to add_timer() calls from
> > 	a CPU that is going offline.  The hope would be that they get
> > 	queued to some other CPU?
> 
> This case is interesting, and I'm no sure what happens here.

It turns out that there is a timer_cpu_modifier() that invokes
migrate_timers() upon CPU_DEAD or CPU_DEAD_FROZEN.  And migrate_timers()
looks like it does what its name says.  And I believe that CPU_DEAD
happens after sparc64's local_irq_enable() window, so we should be OK.

							Thanx, Paul

  reply	other threads:[~2008-09-09 15:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-31 17:33 [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs Paul E. McKenney
2008-09-03  0:16 ` David Miller
2008-09-03  0:42   ` Paul E. McKenney
2008-09-03  9:21     ` David Miller
2008-09-03 15:42       ` Paul E. McKenney
2008-09-09  0:17         ` David Miller
2008-09-09 14:54           ` Paul E. McKenney [this message]
2008-09-09 18:49           ` Manfred Spraul
2008-09-09 19:57             ` David Miller

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