From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Hellstrom Subject: Re: Hibernation out-of-memory problem. Date: Tue, 13 Oct 2009 21:25:13 +0200 Message-ID: <4AD4D419.9000302@vmware.com> References: <4AD0F4D0.2090809@vmware.com> <200910122317.59973.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200910122317.59973.rjw@sisk.pl> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: "Rafael J. Wysocki" Cc: "linux-pm@lists.linux-foundation.org" , "dri-devel@lists.sourceforge.net" List-Id: linux-pm@vger.kernel.org Rafael J. Wysocki wrote: > On Saturday 10 October 2009, Thomas Hellstrom wrote: > >> Hi! >> >> I'm trying to port a graphics DRM device driver over to the new power >> management hooks in >> >> struct dev_pm_ops. >> >> During the "prepare" call, Video RAM contents may be copied either to >> shmem objects or pages allocated using alloc_page(). >> Unfortunately, this seems to lead to the hibernation process running out >> of free pages. >> >> One possible cause is that the function swsusp_shrink_memory() is called >> before the prepare() call, and therefore doesn't free up enough memory. >> >> What would be the correct way around this? Should swsusp_shrink_memory() >> be moved to after prepare(), or is it possible to get some kind of >> notification after user space processes is stopped, but before >> swsusp_shrink_memory()? >> > > There are suspend/hibernation notifiers that can be used for this purpose. > > Thanks, > Rafael > Thanks, Rafael. I tried that and it works fine. Now, it may be that others will hit this problem as well, as the documentation in states that it is safe to make GFP_KERNEL allocations from within a prepare() callback. Such allocations executed in the prepare() preceeding a freeze() will probably make the amount of previously freed memory insufficient. Thanks, Thomas