From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id BDE636B006C for ; Mon, 21 Nov 2011 15:03:08 -0500 (EST) From: "Rafael J. Wysocki" Subject: Re: [PATCH v3] PM/Memory-hotplug: Avoid task freezing failures Date: Mon, 21 Nov 2011 21:05:51 +0100 References: <20111117083042.11419.19871.stgit@srivatsabhat.in.ibm.com> <20111121175242.GE15314@google.com> <4ECA9217.7020205@linux.vnet.ibm.com> In-Reply-To: <4ECA9217.7020205@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201111212105.52210.rjw@sisk.pl> Sender: owner-linux-mm@kvack.org List-ID: To: "Srivatsa S. Bhat" Cc: Tejun Heo , pavel@ucw.cz, lenb@kernel.org, ak@linux.intel.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-mm@kvack.org On Monday, November 21, 2011, Srivatsa S. Bhat wrote: > On 11/21/2011 11:22 PM, Tejun Heo wrote: > > Hello, > > > > On Mon, Nov 21, 2011 at 10:34:40PM +0530, Srivatsa S. Bhat wrote: > >>>> I haven't tested this solution yet. Let me know if this solution looks > >>>> good and I'll send it out as a patch after testing and analyzing some > >>>> corner cases, if any. > >> > >> I tested this, and it works great! I'll send the patch in some time. > > > > Awesome. > > > >>> * I think it would be better to remove direct access to pm_mutex and > >>> use [un]lock_system_sleep() universally. I don't think hinging it > >>> on CONFIG_HIBERNATE_CALLBACKS buys us anything. > >>> > >> > >> Which direct access to pm_mutex are you referring to? > >> Other than suspend/hibernation call paths, I think mem-hotplug is the only > >> subsystem trying to access pm_mutex. I haven't checked thoroughly though. > >> > >> But yes, using lock_system_sleep() for mutually excluding some code path > >> from suspend/hibernation is good, and that is one reason why I wanted > >> to fix this API ASAP. But as long as memory hotplug is the only direct user > >> of pm_mutex, is it justified to remove the CONFIG_HIBERNATE_CALLBACKS > >> restriction and make it generic? I don't know... > >> > >> Or, are you saying that we should use these APIs even in suspend/hibernate > >> call paths? That's not such a bad idea either... > > > > Yeap, all. It's just confusing to have two different types of access > > to a single lock and I don't believe CONFIG_HIBERNATE_CALLBACKS is a > > meaningful optimization in this case. > > > > Ok that sounds good, I'll send a separate patch for that. > Rafael, do you also agree that this would be better? Yes, it would. Thanks, Rafael -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org