From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: [PATCH 5/5] PM/Hibernate: Do not release preallocated memory unnecessarily (rev. 2) Date: Tue, 5 May 2009 10:46:46 +0800 Message-ID: <20090505024646.GA14621@localhost> References: <200905031830.49690.rjw@sisk.pl> <200905040208.43040.rjw@sisk.pl> <200905040222.39062.rjw@sisk.pl> <20090505022427.GA10880@localhost> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20090505022427.GA10880@localhost> Sender: kernel-testers-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Rafael J. Wysocki" Cc: "linux-pm-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org" , Andrew Morton , "pavel-+ZI9xUNit7I@public.gmane.org" , "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" On Tue, May 05, 2009 at 10:24:27AM +0800, Wu Fengguang wrote: > On Mon, May 04, 2009 at 08:22:38AM +0800, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki > > > > Since the hibernation code is now going to use allocations of memory > > to create enough room for the image, it can also use the page frames > > allocated at this stage as image page frames. The low-level > > hibernation code needs to be rearranged for this purpose, but it > > allows us to avoid freeing a great number of pages and allocating > > these same pages once again later, so it generally is worth doing. > > > > [rev. 2: Change the strategy of preallocating memory to allocate as > > many pages as needed to get the right image size in one shot (the > > excessive allocated pages are released afterwards).] > > Rafael, I tried out your patches and found doubled memory shrink speed! > > [ 579.641781] PM: Preallocating image memory ... done (allocated 383900 pages, 128000 image pages kept) > [ 583.087875] PM: Allocated 1535600 kbytes in 3.43 seconds (447.69 MB/s) > For you reference, here is the free memory before/after > hibernate_preallocate_memory(): > > # free > total used free shared buffers cached > Mem: 1933 1917 15 0 0 1845 > -/+ buffers/cache: 72 1861 > Swap: 0 0 0 > > # free > total used free shared buffers cached > Mem: 1933 920 1012 0 0 356 > -/+ buffers/cache: 563 1369 > Swap: 0 0 0 > > It seems that the preallocated memory is not freed on -ENOMEM. Ah, this was my fault. I used to do this debugging trick: @@ -1207,7 +1207,7 @@ int hibernate_preallocate_memory(void) pages, size); swsusp_show_speed(&start, &stop, pages, "Allocated"); - return 0; + return -ENOMEM; err_out: printk(KERN_CONT "\n"); That "return -ENOMEM" should be "error = -ENOMEM" :-) Here is one more run: [ 194.016991] PM: Preallocating image memory ... done (allocated 383897 pages, 128000 image pages kept) [ 196.505999] PM: Allocated 1535588 kbytes in 2.47 seconds (621.69 MB/s) Now the free report is back to normal: # free total used free shared buffers cached Mem: 1933 74 1858 0 0 15 Thanks, Fengguang