From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753338Ab3DVNRK (ORCPT ); Mon, 22 Apr 2013 09:17:10 -0400 Received: from e31.co.us.ibm.com ([32.97.110.149]:59572 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751435Ab3DVNRJ (ORCPT ); Mon, 22 Apr 2013 09:17:09 -0400 Date: Mon, 22 Apr 2013 06:16:44 -0700 From: "Paul E. McKenney" To: Borislav Petkov Cc: Ingo Molnar , x86-ml , lkml , tiwai@suse.de, Thomas Gleixner Subject: Re: irq 16: nobody cared Message-ID: <20130422131644.GH3509@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <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> <20130422080136.GA7080@gmail.com> <20130422091847.GB4637@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130422091847.GB4637@pd.tnic> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13042213-7282-0000-0000-0000166C0452 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 22, 2013 at 11:18:47AM +0200, Borislav Petkov wrote: > On Mon, Apr 22, 2013 at 10:01:36AM +0200, Ingo Molnar wrote: > > Hm, this really smells like a workaround: treating the symptom, not > > the cause. > > Well, I just tested Takashi's add missing synchronize_irq() to the > suspend path of snd_hda_intel and it doesn't help. > > So it could be an issue with this driver or only this hw/driver can > exacerbate RCU this much to trigger the spurious irq machinery. > > > How can an increase in grace-periods break drivers and suspend? Do we > > understand exactly what happens there? > > I'd rather look into Paul's direction here. :) I believe that we need both -- a fix that prevents the stray irq for normal CONFIG_RCU_FAST_NO_HZ grace periods and also expediting grace periods during suspend/resume. I am greedy that way. ;-) Thanx, Paul > > If we do, can we fix that instead of tweaking the RCU timeouts? > > Well, I was under the impression yesterday that we actually want > to switch to expedited grace periods for suspend/resume *anyway*, > regardless of drivers. > > Paul? > > -- > Regards/Gruss, > Boris. > > Sent from a fat crate under my desk. Formatting is fine. > -- >