Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754267Ab1EEN62 (ORCPT ); Thu, 5 May 2011 09:58:28 -0400 Received: from www.linutronix.de ([62.245.132.108]:55403 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754012Ab1EEN61 (ORCPT ); Thu, 5 May 2011 09:58:27 -0400 Date: Thu, 5 May 2011 15:58:19 +0200 (CEST) From: Thomas Gleixner To: Andi Kleen cc: Dave Kleikamp , Chris Mason , Peter Zijlstra , Tim Chen , linux-kernel@vger.kernel.org, lenb@kernel.org, paulmck@us.ibm.com Subject: Re: idle issues running sembench on 128 cpus In-Reply-To: Message-ID: References: <4DC1C95B.4040706@gmail.com> <20110504230349.GC2925@one.firstfloor.org> User-Agent: Alpine 2.02 (LFD 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1170 Lines: 35 On Thu, 5 May 2011, Thomas Gleixner wrote: > On Thu, 5 May 2011, Andi Kleen wrote: > > > No, it does not even need refcounting. We can access it outside of the > > > > Ok. > > > > > lock as this is atomic context called on the cpu which is about to go > > > idle and therefor the device cannot go away. Easy and straightforward > > > fix. > > > > Ok. Patch appended. Looks good? > > Mostly. See below. > > > BTW why must the lock be irqsave? > > Good question. Probably safety frist paranoia :) > > Indeed that code should only be called from irq disabled regions, so > we could avoid the irqsave there. Otherwise that needs to be irqsave > for obvious reasons. Just looked through all the call sites. Both intel_idle and processor_idle notify ENTER with interrups disabled, but EXIT with interrupts enabled. So when we want to remove irqsave from the spinlock that needs to be fixed as well. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/