Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751491AbWEUGxA (ORCPT ); Sun, 21 May 2006 02:53:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751492AbWEUGxA (ORCPT ); Sun, 21 May 2006 02:53:00 -0400 Received: from pne-smtpout2-sn2.hy.skanova.net ([81.228.8.164]:18644 "EHLO pne-smtpout2-sn2.hy.skanova.net") by vger.kernel.org with ESMTP id S1751491AbWEUGw7 (ORCPT ); Sun, 21 May 2006 02:52:59 -0400 Date: Sun, 21 May 2006 08:52:48 +0200 From: Peter Lundkvist To: Andrew Morton Cc: Pavel Machek , linux-kernel@vger.kernel.org, rjw@sisk.pl Subject: Re: [PATCH] Page writeback broken after resume: wb_timer lost Message-ID: <20060521065248.GA5659@localhost> References: <20060520130326.GA6092@localhost> <20060520103728.6f3b3798.akpm@osdl.org> <20060520225018.GC8490@elf.ucw.cz> <20060520171244.4399bc54.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060520171244.4399bc54.akpm@osdl.org> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2303 Lines: 69 On Sat, May 20, 2006 at 05:12:44PM -0700, Andrew Morton wrote: > > Peter, does this fix it? > Yes, it does fix the problem. Hopefully we'll see this fix in the next stable update, because of the risk of data loss. > > From: Andrew Morton > > pdflush is carefully designed to ensure that all wakeups have some > corresponding work to do - if a woken-up pdflush thread discovers that it > hasn't been given any work to do then this is considered an error. > > That all broke when swsusp came along - because a timer-delivered wakeup to a > frozen pdflush thread will just get lost. This causes the pdflush thread to > get lost as well: the writeback timer is supposed to be re-armed by pdflush in > process context, but pdflush doesn't execute the callout which does this. > > Fix that up by ignoring the return value from try_to_freeze(): jsut proceed, > see if we have any work pending and only go back to sleep if that is not the > case. > > > Signed-off-by: Andrew Morton > --- > > mm/pdflush.c | 9 ++------- > 1 files changed, 2 insertions(+), 7 deletions(-) > > diff -puN mm/pdflush.c~pdflush-handle-resume-wakeups mm/pdflush.c > --- devel/mm/pdflush.c~pdflush-handle-resume-wakeups 2006-05-20 17:02:21.000000000 -0700 > +++ devel-akpm/mm/pdflush.c 2006-05-20 17:11:25.000000000 -0700 > @@ -104,13 +104,8 @@ static int __pdflush(struct pdflush_work > list_move(&my_work->list, &pdflush_list); > my_work->when_i_went_to_sleep = jiffies; > spin_unlock_irq(&pdflush_lock); > - > schedule(); > - if (try_to_freeze()) { > - spin_lock_irq(&pdflush_lock); > - continue; > - } > - > + try_to_freeze(); > spin_lock_irq(&pdflush_lock); > if (!list_empty(&my_work->list)) { > printk("pdflush: bogus wakeup!\n"); > @@ -118,7 +113,7 @@ static int __pdflush(struct pdflush_work > continue; > } > if (my_work->fn == NULL) { > - printk("pdflush: NULL work function\n"); > + printk("pflush: resuming\n"); > continue; > } > spin_unlock_irq(&pdflush_lock); > _ > > > - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/