From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [PATCH 0/2] Improve writeout pattern from xfs_flush_pages() Date: Thu, 4 Aug 2011 14:07:24 +0200 Message-ID: <20110804120724.GA20800@quack.suse.cz> References: <1312404545-15400-1-git-send-email-jack@suse.cz> <20110803214206.GA20477@infradead.org> <20110804103616.GF17196@quack.suse.cz> <20110804104210.GA30823@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org To: Christoph Hellwig Return-path: Received: from cantor2.suse.de ([195.135.220.15]:38898 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752786Ab1HDMH0 (ORCPT ); Thu, 4 Aug 2011 08:07:26 -0400 Content-Disposition: inline In-Reply-To: <20110804104210.GA30823@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu 04-08-11 06:42:10, Christoph Hellwig wrote: > On Thu, Aug 04, 2011 at 12:36:16PM +0200, Jan Kara wrote: > > > The first one actually is a synchronous writeout, just implemented in > > > a rather odd way by doing the xfs_ioend_wait right after it, so your > > > change is actively harmful for it. > > Oh, right. BTW cannot be truncate livelocked on a busy file because of > > that xfs_ioend_wait()? > > Not really. We requite the iolock for new writes to start, and truncate > holds it exclusively. But I'm working on a series for 3.2 to remove > xfs_ioend_wait and just rely on inode_dio_wait for direct I/O, so it > will be gone soon. At this point I'll also have to switch to > filemap_write_and_wait_range for this caller. > > > > The third one is opportunistic writeout if a file got truncated down on > > > final release. filemap_flush probably is fine here, but there's no need > > > for a range version. If you replace it with filemap_flush please also > > > kill the useless wrapper while you're at it. > > Do you mean xfs_flush_pages()? OK, I can do that. > > Yes, xfs_flush_pages should go - at least he async version and its > abuse of the buffer flags. Hmm, BTW, shouldn't the call to xfs_flush_pages() in xfs_file_buffered_aio_write() be converted to an asynchronous one? I don't quite see a point in waiting for io completion... Generally, flushing of the inode there seems of limited usefulness to me since that inode could be just a tiny victim not holding much delayallocated blocks. Honza -- Jan Kara SUSE Labs, CR