From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 3/4] PM/Hibernate: Use memory allocations to free memory (rev. 2) Date: Mon, 4 May 2009 21:52:14 +0200 Message-ID: <200905042152.15564.rjw@sisk.pl> References: <200905031822.55260.rjw@sisk.pl> <20090504093121.GB30306@elf.ucw.cz> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090504093121.GB30306-I/5MKhXcvmPrBKCeMvbIDA@public.gmane.org> Content-Disposition: inline Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: Text/Plain; charset="us-ascii" To: Pavel Machek Cc: Wu Fengguang , Andrew Morton , torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, alan-jenkins-cCz0Lq7MMjm9FHfhHBbuYA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-testers-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org On Monday 04 May 2009, Pavel Machek wrote: > On Sun 2009-05-03 18:22:54, Rafael J. Wysocki wrote: > > On Sunday 03 May 2009, Wu Fengguang wrote: > > > On Sun, May 03, 2009 at 02:24:20AM +0200, Rafael J. Wysocki wrote: > > > > From: Rafael J. Wysocki > > > > > > > > Modify the hibernation memory shrinking code so that it will make > > > > memory allocations to free memory instead of using an artificial > > > > memory shrinking mechanism for that. Remove the shrinking of > > > > memory from the suspend-to-RAM code, where it is not really > > > > necessary. Finally, remove the no longer used memory shrinking > > > > functions from mm/vmscan.c . > > > > > > > > [rev. 2: Use the existing memory bitmaps for marking preallocated > > > > image pages and use swsusp_free() from releasing them, introduce > > > > GFP_IMAGE, add comments describing the memory shrinking strategy.] > > > > > > > > Signed-off-by: Rafael J. Wysocki > > > > --- > > > > kernel/power/main.c | 20 ------ > > > > kernel/power/snapshot.c | 132 +++++++++++++++++++++++++++++++++----------- > > > > mm/vmscan.c | 142 ------------------------------------------------ > > > > 3 files changed, 101 insertions(+), 193 deletions(-) > > > > > > > > Index: linux-2.6/kernel/power/snapshot.c > > > > =================================================================== > > > > --- linux-2.6.orig/kernel/power/snapshot.c > > > > +++ linux-2.6/kernel/power/snapshot.c > > > > @@ -1066,41 +1066,97 @@ void swsusp_free(void) > > > > buffer = NULL; > > > > } > > > > > > > > +/* Helper functions used for the shrinking of memory. */ > > > > + > > > > +#ifdef CONFIG_HIGHMEM > > > > +#define GFP_IMAGE (GFP_KERNEL | __GFP_HIGHMEM | __GFP_NO_OOM_KILL) > > > > +#else > > > > +#define GFP_IMAGE (GFP_KERNEL | __GFP_NO_OOM_KILL) > > > > +#endif > > > > > > The CONFIG_HIGHMEM test is not necessary: __GFP_HIGHMEM is always defined. > > > > > > > +#define SHRINK_BITE 10000 > > > > > > This is ~40MB. A full scan of (for example) 8G pages will be time > > > consuming, not to mention we have to do it 2*(8G-500M)/40M = 384 times! > > > > > > Can we make it a LONG_MAX? > > > > No, I don't think so. The problem is the number of pages we'll need to copy > > is generally shrinking as we allocate memory, so we can't do that in one shot. > > > > We can make it a greater number, but I don't really think it would be a good > > idea to make it greater than 100 MB. > > Well, even 100MB is quite big: on 128MB machine, that will probably > mean freeing all the memory (instead of "as much as needed"). And that > memory needs to go to disk, so it will be slow. But we're going to free it anyway? Rafael From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755196AbZEDTw3 (ORCPT ); Mon, 4 May 2009 15:52:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754052AbZEDTwS (ORCPT ); Mon, 4 May 2009 15:52:18 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:43750 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752962AbZEDTwR (ORCPT ); Mon, 4 May 2009 15:52:17 -0400 From: "Rafael J. Wysocki" To: Pavel Machek Subject: Re: [PATCH 3/4] PM/Hibernate: Use memory allocations to free memory (rev. 2) Date: Mon, 4 May 2009 21:52:14 +0200 User-Agent: KMail/1.11.2 (Linux/2.6.30-rc4-rjw; KDE/4.2.2; x86_64; ; ) Cc: Wu Fengguang , Andrew Morton , torvalds@linux-foundation.org, jens.axboe@oracle.com, alan-jenkins@tuffmail.co.uk, linux-kernel@vger.kernel.org, kernel-testers@vger.kernel.org, linux-pm@lists.linux-foundation.org References: <200905031822.55260.rjw@sisk.pl> <20090504093121.GB30306@elf.ucw.cz> In-Reply-To: <20090504093121.GB30306@elf.ucw.cz> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200905042152.15564.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 04 May 2009, Pavel Machek wrote: > On Sun 2009-05-03 18:22:54, Rafael J. Wysocki wrote: > > On Sunday 03 May 2009, Wu Fengguang wrote: > > > On Sun, May 03, 2009 at 02:24:20AM +0200, Rafael J. Wysocki wrote: > > > > From: Rafael J. Wysocki > > > > > > > > Modify the hibernation memory shrinking code so that it will make > > > > memory allocations to free memory instead of using an artificial > > > > memory shrinking mechanism for that. Remove the shrinking of > > > > memory from the suspend-to-RAM code, where it is not really > > > > necessary. Finally, remove the no longer used memory shrinking > > > > functions from mm/vmscan.c . > > > > > > > > [rev. 2: Use the existing memory bitmaps for marking preallocated > > > > image pages and use swsusp_free() from releasing them, introduce > > > > GFP_IMAGE, add comments describing the memory shrinking strategy.] > > > > > > > > Signed-off-by: Rafael J. Wysocki > > > > --- > > > > kernel/power/main.c | 20 ------ > > > > kernel/power/snapshot.c | 132 +++++++++++++++++++++++++++++++++----------- > > > > mm/vmscan.c | 142 ------------------------------------------------ > > > > 3 files changed, 101 insertions(+), 193 deletions(-) > > > > > > > > Index: linux-2.6/kernel/power/snapshot.c > > > > =================================================================== > > > > --- linux-2.6.orig/kernel/power/snapshot.c > > > > +++ linux-2.6/kernel/power/snapshot.c > > > > @@ -1066,41 +1066,97 @@ void swsusp_free(void) > > > > buffer = NULL; > > > > } > > > > > > > > +/* Helper functions used for the shrinking of memory. */ > > > > + > > > > +#ifdef CONFIG_HIGHMEM > > > > +#define GFP_IMAGE (GFP_KERNEL | __GFP_HIGHMEM | __GFP_NO_OOM_KILL) > > > > +#else > > > > +#define GFP_IMAGE (GFP_KERNEL | __GFP_NO_OOM_KILL) > > > > +#endif > > > > > > The CONFIG_HIGHMEM test is not necessary: __GFP_HIGHMEM is always defined. > > > > > > > +#define SHRINK_BITE 10000 > > > > > > This is ~40MB. A full scan of (for example) 8G pages will be time > > > consuming, not to mention we have to do it 2*(8G-500M)/40M = 384 times! > > > > > > Can we make it a LONG_MAX? > > > > No, I don't think so. The problem is the number of pages we'll need to copy > > is generally shrinking as we allocate memory, so we can't do that in one shot. > > > > We can make it a greater number, but I don't really think it would be a good > > idea to make it greater than 100 MB. > > Well, even 100MB is quite big: on 128MB machine, that will probably > mean freeing all the memory (instead of "as much as needed"). And that > memory needs to go to disk, so it will be slow. But we're going to free it anyway? Rafael