From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964941AbWJWP37 (ORCPT ); Mon, 23 Oct 2006 11:29:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964942AbWJWP37 (ORCPT ); Mon, 23 Oct 2006 11:29:59 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:55716 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S964941AbWJWP36 (ORCPT ); Mon, 23 Oct 2006 11:29:58 -0400 Date: Mon, 23 Oct 2006 17:29:16 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andrew Morton , LKML Subject: Re: [PATCH -mm] swsusp: Improve handling of highmem Message-ID: <20061023152916.GA8418@elf.ucw.cz> References: <200610142156.05161.rjw@sisk.pl> <20061023150444.GC31273@elf.ucw.cz> <200610231722.57560.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200610231722.57560.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Currently swsusp saves the contents of highmem pages by copying them to the > > > normal zone which is quite inefficient (eg. it requires two normal pages to be > > > used for saving one highmem page). This may be improved by using highmem > > > for saving the contents of saveable highmem pages. > > ... > > > include/linux/suspend.h | 9 > > > kernel/power/power.h | 2 > > > kernel/power/snapshot.c | 841 ++++++++++++++++++++++++++++++++++++------------ > > > kernel/power/swap.c | 2 > > > kernel/power/swsusp.c | 53 +-- > > > kernel/power/user.c | 2 > > > mm/vmscan.c | 3 > > > > Well, I just hoped that highmem would quietly die out... > > > > ... > > > +static struct page *alloc_image_page(gfp_t gfp_mask) { > > > + struct page *page; > > > > { should go on new line. > > Ah, yes, thanks. I'll fix this later if you don't mind. Ok. > > > memory_bm_position_reset(orig_bm); > > > memory_bm_position_reset(copy_bm); > > > do { > > > pfn = memory_bm_next_pfn(orig_bm); > > > - if (likely(pfn != BM_END_OF_MAP)) { 1) ############################################## > > > - struct page *page; > > > - void *src; > > > - > > > - page = pfn_to_page(pfn); > > > - src = page_address(page); > > > - page = pfn_to_page(memory_bm_next_pfn(copy_bm)); > > > - copy_data_page(page_address(page), src); > > > - } > > > + if (likely(pfn != BM_END_OF_MAP)) 2) ############################################## > > > + copy_data_page(memory_bm_next_pfn(copy_bm), pfn); > > > } while (pfn != BM_END_OF_MAP); 3) #################################### > > > } > > > > While(1) and "if (pfn != BM_END_OF_MAP) { ...break; } ? Why do you > > need to test pfn != BM_END_OF_MAP *three* times? > > Why? It's two times, and I don't like while(1) loops, really. I see three of them, and while(1) loop is probably best solution here... "Too scared of break; so I copy conditions"? ;-). > > > @@ -1233,6 +1233,9 @@ out: > > > } > > > if (!all_zones_ok) { > > > cond_resched(); > > > + > > > + try_to_freeze(); > > > + > > > goto loop_again; > > > } > > > > What is this? > > :-) > > This is needed because during the resume there likely are no free pages in the > highmem zone which makes kswapd spin forever, but we have to freeze it before > the image is restored. Could that happen with current code, too? (I'm trying to sense if this should be merged now as a separate patch). Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html