From: Jeff Moyer Subject: Re: [RFC] ext4: Don't send extra barrier during fsync if there are no dirty pages. Date: Thu, 05 Aug 2010 16:44:53 -0400 Message-ID: References: <20100429235102.GC15607@tux1.beaverton.ibm.com> <1272934667.2544.3.camel@mingming-laptop> <4BE02C45.6010608@redhat.com> <20100504154553.GA22777@infradead.org> <20100630124832.GA1333@thunk.org> <4C5818A1.9070102@redhat.com> <20100804233206.GA2901@thunk.org> <4C5A1FDC.3010700@redhat.com> <20100805161745.GG2901@thunk.org> <20100805203928.GM2901@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Avi Kivity , Christoph Hellwig , Ric Wheeler , Mingming Cao , djwong@us.ibm.com, linux-ext4 , linux-kernel , Keith Mannthey , Mingming Cao To: "Ted Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:20733 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758865Ab0HEUpC (ORCPT ); Thu, 5 Aug 2010 16:45:02 -0400 In-Reply-To: <20100805203928.GM2901@thunk.org> (Ted Ts'o's message of "Thu, 5 Aug 2010 16:39:28 -0400") Sender: linux-ext4-owner@vger.kernel.org List-ID: "Ted Ts'o" writes: > On Thu, Aug 05, 2010 at 03:13:44PM -0400, Jeff Moyer wrote: >> > IO_CMD_FSYNC doesn't exist right now, but sure, it means we don't have >> >> Well, there's IOCB_CMD_FSYNC. But still, this isn't the same thing as >> what's requested. If I understand correctly, what is requested is a >> mechanism to flush out all data for multiple file descriptors and follow >> that with a single barrier/flush (and yes, Ted did give a summary of the >> commands that would be required to accomplish that). >> >> There still remains the question of why this should be tied to the AIO >> submission interface. > > I don't think it should, personally. The only excuse might be if > someone wanted to do an asynchronous fsync(), but I don't think that > makes sense in most cases. In case it wasn't clear, we are in agreement on this. Cheers, Jeff