Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755514Ab3DVIBq (ORCPT ); Mon, 22 Apr 2013 04:01:46 -0400 Received: from mail-we0-f172.google.com ([74.125.82.172]:51770 "EHLO mail-we0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755041Ab3DVIBo (ORCPT ); Mon, 22 Apr 2013 04:01:44 -0400 Date: Mon, 22 Apr 2013 10:01:36 +0200 From: Ingo Molnar To: Borislav Petkov Cc: "Paul E. McKenney" , x86-ml , lkml , tiwai@suse.de, Thomas Gleixner Subject: Re: irq 16: nobody cared Message-ID: <20130422080136.GA7080@gmail.com> References: <20130421163002.GB3509@linux.vnet.ibm.com> <20130421165653.GA4623@pd.tnic> <20130421181035.GC4559@pd.tnic> <20130421185609.GD3509@linux.vnet.ibm.com> <20130421190655.GA5807@pd.tnic> <20130421203447.GE3509@linux.vnet.ibm.com> <20130421205139.GC5807@pd.tnic> <20130421214241.GA4593@pd.tnic> <20130421220015.GF3509@linux.vnet.ibm.com> <20130421221242.GB4593@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130421221242.GB4593@pd.tnic> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1247 Lines: 32 * Borislav Petkov wrote: > From 3c155e9a22036839c09d98a4acbc7e17a5a3783c Mon Sep 17 00:00:00 2001 > From: Borislav Petkov > Date: Sun, 21 Apr 2013 23:56:15 +0200 > Subject: [PATCH] RCU: Expedite grace periods during suspend/resume > > Paul says CONFIG_RCU_FAST_NO_HZ can increase grace-period durations by a > factor of four. This, in turn, can change timings during suspend and can > delay interrupts handling, leading to "IRQ XX: nobody cared" splats and > the machine disabling those interrupt lines for no sensible reason. > > Thus, we want to temporarily switch to expedited grace periods when > suspending the box and return to normal settings when resuming. This > patch does exactly that. Hm, this really smells like a workaround: treating the symptom, not the cause. How can an increase in grace-periods break drivers and suspend? Do we understand exactly what happens there? If we do, can we fix that instead of tweaking the RCU timeouts? Thanks, Ingo -- 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/