From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [RFD] swsusp problem: Drivers allocate much memory during suspend (was: Re: 2.6.21-rc5: swsusp: Not enough free memory) Date: Sat, 14 Apr 2007 00:57:35 +0200 Message-ID: <200704140057.35829.rjw@sisk.pl> References: <460B6E4B.3060004@gmail.com> <20070413224053.GT28264@elf.ucw.cz> <1176504306.7112.206.camel@nigel.suspend2.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <1176504306.7112.206.camel@nigel.suspend2.net> Content-Disposition: inline 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: Nigel Cunningham Cc: linux-pm@lists.osdl.org, Jiri Slaby , Pavel Machek , Linux kernel mailing list List-Id: linux-pm@vger.kernel.org On Saturday, 14 April 2007 00:45, Nigel Cunningham wrote: > Hi. > = > On Sat, 2007-04-14 at 00:40 +0200, Pavel Machek wrote: > > Hi! > > = > > > > > > > Well, it looks like someone allocated about 6000 pages after = we had freed > > > > > > > enough memory for suspending. > > > > > > = > > > > > > We have a tunable allowance in Suspend2 for this, because fglrx > > > > > > allocates a lot of pages in its suspend routine if DRI is enabl= ed. I > > > > > > think some other drivers do too, but fglrx is the main one I kn= ow. > > > > > = > > > > > I wasn't aware of that, thanks for the information. > > > > > = > > > > > I think this means we'll probably need to add a tunable, similar = to image_size, > > > > > that will allow the users to specify how much spare memory they w= ant to reserve > > > > > for suspending (instead of the constant PAGES_FOR_IO). IMO we ca= n call it > > > > > 'spare_memory'. > > > > = > > > > Just increase PAGES_FOR_IO. This should not be tunable. > > > = > > > Well, I'm not sure. First, we don't really know what the value of it= should be > > > and this alone is a good enough reason for making it tunable, IMHO. = Second, I > > > think different systems may need different PAGES_FOR_IO and taking ju= st the > > > maximum (even if we learn how much that actually is) seems to be wast= eful in > > = > > Well, it is wasteful as in "we save slightly smaller image than we > > could". That's okay with me. > = > No. If the driver can't allocate the memory, your call to device_suspend > will fail. This isn't about image size but about success or failure to > hibernate. If we take PAGES_FOR_IO to be the maximum over all possible configurations that can hibernate, the majority of systems will just create smaller images= than they could have created for smaller PAGES_FOR_IO, but all of them will be able to hibernate. :-) Greetings, Rafael