From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755547AbZINNNm (ORCPT ); Mon, 14 Sep 2009 09:13:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755455AbZINNNl (ORCPT ); Mon, 14 Sep 2009 09:13:41 -0400 Received: from cantor.suse.de ([195.135.220.2]:45460 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755457AbZINNNk (ORCPT ); Mon, 14 Sep 2009 09:13:40 -0400 Date: Mon, 14 Sep 2009 15:13:42 +0200 From: Jan Kara To: Jens Axboe Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, chris.mason@oracle.com, hch@infradead.org, tytso@mit.edu, akpm@linux-foundation.org, jack@suse.cz, trond.myklebust@fys.uio.no Subject: Re: [PATCH 5/7] writeback: inline allocation failure handling in bdi_alloc_queue_work() Message-ID: <20090914131342.GI24075@duck.suse.cz> References: <1252920994-11141-1-git-send-email-jens.axboe@oracle.com> <1252920994-11141-6-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1252920994-11141-6-git-send-email-jens.axboe@oracle.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 14-09-09 11:36:32, Jens Axboe wrote: > This gets rid of work == NULL in bdi_queue_work() and puts the > OOM handling where it belongs. Looks good. Acked-by: Jan Kara Honza > > Signed-off-by: Jens Axboe > --- > fs/fs-writeback.c | 55 +++++++++++++++++++++++++++------------------------- > 1 files changed, 29 insertions(+), 26 deletions(-) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index d7592c7..5cd8b3b 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -139,21 +139,19 @@ static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) > > static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) > { > - if (work) { > - work->seen = bdi->wb_mask; > - BUG_ON(!work->seen); > - atomic_set(&work->pending, bdi->wb_cnt); > - BUG_ON(!bdi->wb_cnt); > + work->seen = bdi->wb_mask; > + BUG_ON(!work->seen); > + atomic_set(&work->pending, bdi->wb_cnt); > + BUG_ON(!bdi->wb_cnt); > > - /* > - * Make sure stores are seen before it appears on the list > - */ > - smp_mb(); > + /* > + * Make sure stores are seen before it appears on the list > + */ > + smp_mb(); > > - spin_lock(&bdi->wb_lock); > - list_add_tail_rcu(&work->list, &bdi->work_list); > - spin_unlock(&bdi->wb_lock); > - } > + spin_lock(&bdi->wb_lock); > + list_add_tail_rcu(&work->list, &bdi->work_list); > + spin_unlock(&bdi->wb_lock); > > /* > * If the default thread isn't there, make sure we add it. When > @@ -165,14 +163,12 @@ static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) > struct bdi_writeback *wb = &bdi->wb; > > /* > - * If we failed allocating the bdi work item, wake up the wb > - * thread always. As a safety precaution, it'll flush out > - * everything > + * End work now if this wb has no dirty IO pending. Otherwise > + * wakeup the handling thread > */ > - if (!wb_has_dirty_io(wb)) { > - if (work) > - wb_clear_pending(wb, work); > - } else if (wb->task) > + if (!wb_has_dirty_io(wb)) > + wb_clear_pending(wb, work); > + else if (wb->task) > wake_up_process(wb->task); > } > } > @@ -192,11 +188,20 @@ static void bdi_alloc_queue_work(struct backing_dev_info *bdi, > { > struct bdi_work *work; > > + /* > + * This is WB_SYNC_NONE writeback, so if allocation fails just > + * wakeup the thread for old dirty data writeback > + */ > work = kmalloc(sizeof(*work), GFP_ATOMIC); > - if (work) > + if (work) { > bdi_work_init(work, wbc); > + bdi_queue_work(bdi, work); > + } else { > + struct bdi_writeback *wb = &bdi->wb; > > - bdi_queue_work(bdi, work); > + if (wb->task) > + wake_up_process(wb->task); > + } > } > > void bdi_start_writeback(struct writeback_control *wbc) > @@ -852,10 +857,8 @@ static void bdi_writeback_all(struct writeback_control *wbc) > rcu_read_lock(); > > list_for_each_entry(bdi, &bdi_list, bdi_list) { > - if (!bdi_has_dirty_io(bdi)) > - continue; > - > - bdi_alloc_queue_work(bdi, wbc); > + if (bdi_has_dirty_io(bdi)) > + bdi_alloc_queue_work(bdi, wbc); > } > > rcu_read_unlock(); > -- > 1.6.4.1.207.g68ea > -- Jan Kara SUSE Labs, CR