From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751188AbZH1XGb (ORCPT ); Fri, 28 Aug 2009 19:06:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750872AbZH1XGb (ORCPT ); Fri, 28 Aug 2009 19:06:31 -0400 Received: from mail2.shareable.org ([80.68.89.115]:37318 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750772AbZH1XGa (ORCPT ); Fri, 28 Aug 2009 19:06:30 -0400 Date: Sat, 29 Aug 2009 00:06:23 +0100 From: Jamie Lokier To: Christoph Hellwig Cc: Ulrich Drepper , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: adding proper O_SYNC/O_DSYNC, was Re: O_DIRECT and barriers Message-ID: <20090828230623.GD8036@shareable.org> References: <20090821135403.GA6208@shareable.org> <20090821142635.GB30617@infradead.org> <20090821152459.GC6929@shareable.org> <20090821174525.GA28861@infradead.org> <20090822005006.GA22530@shareable.org> <20090824023422.GA775@infradead.org> <20090827143459.GB31453@shareable.org> <20090827171044.GA5427@infradead.org> <4A96C14C.8040105@redhat.com> <20090828154647.GA15808@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090828154647.GA15808@infradead.org> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christoph Hellwig wrote: > - given that our current O_SYNC really is and always has been actuall > Posix O_DSYNC Are you sure about this? >>From http://www-01.ibm.com/support/docview.wss?uid=isg1IZ01704 : Error description LINUX O_DIRECT/O_SYNC TAKES TOO MANY IOS Problem summary On AIX, the O_SYNC and O_DSYNC are different values and performance improvement are available because the inode does not need to be flushed for mtime changes only. On Linux the flags are the same, so performance is lost. when databases open files with O_DIRECT and O_SYNC. -- Jamie