From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752754AbZIYAwq (ORCPT ); Thu, 24 Sep 2009 20:52:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751894AbZIYAwp (ORCPT ); Thu, 24 Sep 2009 20:52:45 -0400 Received: from mga03.intel.com ([143.182.124.21]:9231 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751596AbZIYAwp (ORCPT ); Thu, 24 Sep 2009 20:52:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.44,448,1249282800"; d="scan'208";a="191452640" Date: Fri, 25 Sep 2009 08:52:41 +0800 From: Wu Fengguang To: Jens Axboe Cc: "linux-kernel@vger.kernel.org" , "Li, Shaohua" , "chris.mason@oracle.com" , "jack@suse.cz" Subject: Re: [PATCH 06/10] writeback: improve readability of the wb_writeback() continue/break logic Message-ID: <20090925005241.GC6190@localhost> References: <1253803236-20760-1-git-send-email-jens.axboe@oracle.com> <1253803236-20760-7-git-send-email-jens.axboe@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1253803236-20760-7-git-send-email-jens.axboe@oracle.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 24, 2009 at 10:40:32PM +0800, Jens Axboe wrote: > And throw some comments in there, too. Nice cleanup! Reviewed-by: Wu Fengguang > Signed-off-by: Jens Axboe > --- > fs/fs-writeback.c | 43 +++++++++++++++++++++++-------------------- > 1 files changed, 23 insertions(+), 20 deletions(-) > > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index 916e834..15e375b 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -750,29 +750,32 @@ static long wb_writeback(struct bdi_writeback *wb, > wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; > > /* > - * If we ran out of stuff to write, bail unless more_io got set > + * If we consumed everything, see if we have more > */ > - if (wbc.nr_to_write > 0) { > - if (wbc.more_io) { > - if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) > - continue; > - /* > - * Nothing written. Wait for some inode to > - * become available for writeback. Otherwise > - * we'll just busyloop. > - */ > - spin_lock(&inode_lock); > - if (!list_empty(&wb->b_more_io)) { > - inode = list_entry( > - wb->b_more_io.prev, > - struct inode, i_list); > - inode_wait_for_writeback(inode); > - } > - spin_unlock(&inode_lock); > - continue; > - } > + if (wbc.nr_to_write <= 0) > + continue; > + /* > + * Didn't write everything and we don't have more IO, bail > + */ > + if (!wbc.more_io) > break; > + /* > + * Did we write something? Try for more > + */ > + if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) > + continue; > + /* > + * Nothing written. Wait for some inode to > + * become available for writeback. Otherwise > + * we'll just busyloop. > + */ > + spin_lock(&inode_lock); > + if (!list_empty(&wb->b_more_io)) { > + inode = list_entry(wb->b_more_io.prev, > + struct inode, i_list); > + inode_wait_for_writeback(inode); > } > + spin_unlock(&inode_lock); > } > > return wrote; > -- > 1.6.4.1.207.g68ea