From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754970Ab3HRDR2 (ORCPT ); Sat, 17 Aug 2013 23:17:28 -0400 Received: from relay4-d.mail.gandi.net ([217.70.183.196]:39499 "EHLO relay4-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753812Ab3HRDR1 (ORCPT ); Sat, 17 Aug 2013 23:17:27 -0400 X-Originating-IP: 50.43.39.152 Date: Sat, 17 Aug 2013 20:17:17 -0700 From: Josh Triplett To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, Borislav Petkov , Borislav Petkov Subject: Re: [PATCH tip/core/rcu 01/11] rcu: Expedite grace periods during suspend/resume Message-ID: <20130818031717.GL28923@leaf> References: <20130818013735.GA27234@linux.vnet.ibm.com> <1376789876-27594-1-git-send-email-paulmck@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1376789876-27594-1-git-send-email-paulmck@linux.vnet.ibm.com> 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 On Sat, Aug 17, 2013 at 06:37:46PM -0700, Paul E. McKenney wrote: > From: Borislav Petkov > > CONFIG_RCU_FAST_NO_HZ can increase grace-period durations by up to > a factor of four, which can result in long suspend and resume times. > Thus, this commit temporarily switches to expedited grace periods when > suspending the box and return to normal settings when resuming. > > [ paulmck: This also papers over an audio/irq bug, but hopefully that will > be fixed soon. ] > > Signed-off-by: Borislav Petkov > Signed-off-by: Paul E. McKenney This patch still seems like a hack, and there *ought* to be a better general solution to avoid excessive grace-period latency. Nonetheless, in the absence of such a solution, Reviewed-by: Josh Triplett