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
Date: Tue, 09 Sep 2008 14:54:53 +0000 [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
WARNING: multiple messages have this Message-ID (diff)
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
next prev parent reply other threads:[~2008-09-09 14:54 UTC|newest]
Thread overview: 18+ 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
2008-08-31 17:33 ` Paul E. McKenney
2008-09-03 0:16 ` [PATCH] prevent sparc64 from invoking irq handlers on offline David Miller
2008-09-03 0:16 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs David Miller
2008-09-03 0:42 ` [PATCH] prevent sparc64 from invoking irq handlers on offline Paul E. McKenney
2008-09-03 0:42 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs Paul E. McKenney
2008-09-03 9:21 ` [PATCH] prevent sparc64 from invoking irq handlers on offline David Miller
2008-09-03 9:21 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs David Miller
2008-09-03 15:42 ` [PATCH] prevent sparc64 from invoking irq handlers on offline Paul E. McKenney
2008-09-03 15:42 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs Paul E. McKenney
2008-09-09 0:17 ` [PATCH] prevent sparc64 from invoking irq handlers on offline David Miller
2008-09-09 0:17 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs David Miller
2008-09-09 14:54 ` Paul E. McKenney [this message]
2008-09-09 14:54 ` Paul E. McKenney
2008-09-09 18:49 ` [PATCH] prevent sparc64 from invoking irq handlers on offline Manfred Spraul
2008-09-09 18:49 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs Manfred Spraul
2008-09-09 19:57 ` [PATCH] prevent sparc64 from invoking irq handlers on offline David Miller
2008-09-09 19:57 ` [PATCH] prevent sparc64 from invoking irq handlers on offline CPUs David Miller
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