From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755434Ab1EFQIy (ORCPT ); Fri, 6 May 2011 12:08:54 -0400 Received: from cantor2.suse.de ([195.135.220.15]:49516 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752712Ab1EFQIx (ORCPT ); Fri, 6 May 2011 12:08:53 -0400 Date: Fri, 6 May 2011 18:08:47 +0200 From: Jan Kara To: Wu Fengguang Cc: Andrew Morton , LKML , Jan Kara , Dave Chinner , Christoph Hellwig , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 01/17] writeback: introduce wbc.tagged_sync for the WB_SYNC_NONE sync stage Message-ID: <20110506160847.GG18982@quack.suse.cz> References: <20110506030821.523093711@intel.com> <20110506031611.917773937@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110506031611.917773937@intel.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 06-05-11 11:08:22, Wu Fengguang wrote: > sync(2) is performed in two stages: the WB_SYNC_NONE sync and the > WB_SYNC_ALL sync. Tag the first stage with wbc.tagged_sync and do > livelock prevention for it, too. > > Note that writeback_inodes_sb() is called by not only sync(), they are > treated the same because the other callers also need livelock prevention. > > Impact: It changes the order in which pages/inodes are synced to disk. > Now in the WB_SYNC_NONE stage, it won't proceed to write the next inode > until finished with the current inode. You can add: Acked-by: Jan Kara > CC: Jan Kara > CC: Dave Chinner > Signed-off-by: Wu Fengguang > --- > fs/ext4/inode.c | 4 ++-- > fs/fs-writeback.c | 9 +++++---- > include/linux/writeback.h | 1 + > mm/page-writeback.c | 4 ++-- > 4 files changed, 10 insertions(+), 8 deletions(-) > > --- linux-next.orig/fs/fs-writeback.c 2011-05-05 23:29:51.000000000 +0800 > +++ linux-next/fs/fs-writeback.c 2011-05-05 23:30:22.000000000 +0800 > @@ -36,6 +36,7 @@ struct wb_writeback_work { > long nr_pages; > struct super_block *sb; > enum writeback_sync_modes sync_mode; > + unsigned int tagged_sync:1; > unsigned int for_kupdate:1; > unsigned int range_cyclic:1; > unsigned int for_background:1; > @@ -650,6 +651,7 @@ static long wb_writeback(struct bdi_writ > { > struct writeback_control wbc = { > .sync_mode = work->sync_mode, > + .tagged_sync = work->tagged_sync, > .older_than_this = NULL, > .for_kupdate = work->for_kupdate, > .for_background = work->for_background, > @@ -657,7 +659,7 @@ static long wb_writeback(struct bdi_writ > }; > unsigned long oldest_jif; > long wrote = 0; > - long write_chunk; > + long write_chunk = MAX_WRITEBACK_PAGES; > struct inode *inode; > > if (wbc.for_kupdate) { > @@ -683,9 +685,7 @@ static long wb_writeback(struct bdi_writ > * (quickly) tag currently dirty pages > * (maybe slowly) sync all tagged pages > */ > - if (wbc.sync_mode == WB_SYNC_NONE) > - write_chunk = MAX_WRITEBACK_PAGES; > - else > + if (wbc.sync_mode == WB_SYNC_ALL || wbc.tagged_sync) > write_chunk = LONG_MAX; > > wbc.wb_start = jiffies; /* livelock avoidance */ > @@ -1193,6 +1193,7 @@ void writeback_inodes_sb_nr(struct super > struct wb_writeback_work work = { > .sb = sb, > .sync_mode = WB_SYNC_NONE, > + .tagged_sync = 1, > .done = &done, > .nr_pages = nr, > }; > --- linux-next.orig/include/linux/writeback.h 2011-05-05 23:29:51.000000000 +0800 > +++ linux-next/include/linux/writeback.h 2011-05-05 23:30:22.000000000 +0800 > @@ -47,6 +47,7 @@ struct writeback_control { > unsigned encountered_congestion:1; /* An output: a queue is full */ > unsigned for_kupdate:1; /* A kupdate writeback */ > unsigned for_background:1; /* A background writeback */ > + unsigned tagged_sync:1; /* do livelock prevention for sync */ > unsigned for_reclaim:1; /* Invoked from the page allocator */ > unsigned range_cyclic:1; /* range_start is cyclic */ > unsigned more_io:1; /* more io to be dispatched */ > --- linux-next.orig/mm/page-writeback.c 2011-05-05 23:29:51.000000000 +0800 > +++ linux-next/mm/page-writeback.c 2011-05-05 23:30:22.000000000 +0800 > @@ -892,12 +892,12 @@ int write_cache_pages(struct address_spa > range_whole = 1; > cycled = 1; /* ignore range_cyclic tests */ > } > - if (wbc->sync_mode == WB_SYNC_ALL) > + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_sync) > tag = PAGECACHE_TAG_TOWRITE; > else > tag = PAGECACHE_TAG_DIRTY; > retry: > - if (wbc->sync_mode == WB_SYNC_ALL) > + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_sync) > tag_pages_for_writeback(mapping, index, end); > done_index = index; > while (!done && (index <= end)) { > --- linux-next.orig/fs/ext4/inode.c 2011-05-05 23:29:51.000000000 +0800 > +++ linux-next/fs/ext4/inode.c 2011-05-05 23:30:22.000000000 +0800 > @@ -2741,7 +2741,7 @@ static int write_cache_pages_da(struct a > index = wbc->range_start >> PAGE_CACHE_SHIFT; > end = wbc->range_end >> PAGE_CACHE_SHIFT; > > - if (wbc->sync_mode == WB_SYNC_ALL) > + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_sync) > tag = PAGECACHE_TAG_TOWRITE; > else > tag = PAGECACHE_TAG_DIRTY; > @@ -2975,7 +2975,7 @@ static int ext4_da_writepages(struct add > } > > retry: > - if (wbc->sync_mode == WB_SYNC_ALL) > + if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_sync) > tag_pages_for_writeback(mapping, index, end); > > while (!ret && wbc->nr_to_write > 0) { > > -- Jan Kara SUSE Labs, CR