From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757323AbYHaRvR (ORCPT ); Sun, 31 Aug 2008 13:51:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755419AbYHaRvF (ORCPT ); Sun, 31 Aug 2008 13:51:05 -0400 Received: from e32.co.us.ibm.com ([32.97.110.150]:45105 "EHLO e32.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755405AbYHaRvD (ORCPT ); Sun, 31 Aug 2008 13:51:03 -0400 Date: Sun, 31 Aug 2008 10:51:00 -0700 From: "Paul E. McKenney" To: Vegard Nossum Cc: linux-kernel@vger.kernel.org, tony.luck@intel.com, jes@sgi.com, manfred@colorfullife.com, akpm@linux-foundation.org Subject: Re: [PATCH] prevent ia64 from invoking irq handlers on offline CPUs Message-ID: <20080831175100.GD7015@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20080831172814.GA15087@linux.vnet.ibm.com> <19f34abd0808311046g47907414wf3ef939d0a7bbfdb@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <19f34abd0808311046g47907414wf3ef939d0a7bbfdb@mail.gmail.com> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Aug 31, 2008 at 07:46:33PM +0200, Vegard Nossum wrote: > On Sun, Aug 31, 2008 at 7:28 PM, Paul E. McKenney > wrote: > > Make ia64 refrain from clearing a given to-be-offlined CPU's bit in the > > cpu_online_mask until it has processed pending irqs. This change > > prevents other CPUs from being blindsided by an apparently offline CPU > > nevertheless changing globally visible state. > > > > Signed-off-by: Paul E. McKenney > > --- > > > > smpboot.c | 3 +-- > > 1 file changed, 1 insertion(+), 2 deletions(-) > > > > diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c > > index bcea81e..7a90f42 100644 > > --- a/arch/ia64/kernel/smpboot.c > > +++ b/arch/ia64/kernel/smpboot.c > > @@ -741,8 +741,6 @@ int __cpu_disable(void) > > return -EBUSY; > > } > > > > - cpu_clear(cpu, cpu_online_map); > > - > > if (migrate_platform_irqs(cpu)) { > > cpu_set(cpu, cpu_online_map); > > return (-EBUSY); > > @@ -751,6 +749,7 @@ int __cpu_disable(void) > > remove_siblinginfo(cpu); > > cpu_clear(cpu, cpu_online_map); > > fixup_irqs(); > > + cpu_clear(cpu, cpu_online_map); > > local_flush_tlb_all(); > > cpu_clear(cpu, cpu_callin_map); > > return 0; > > Hm. Maybe my eyes are going bad. But isn't that now clearing the cpu > both before and after calling fixup_irqs()? I don't believe so... I removed the earlier one and added the later one. Or is there another one hidden somewhere that I missed? Thanx, Paul