Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755939Ab2B0W15 (ORCPT ); Mon, 27 Feb 2012 17:27:57 -0500 Received: from lulu.zabbo.net ([69.168.54.52]:43125 "EHLO lulu.zabbo.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755325Ab2B0W14 (ORCPT ); Mon, 27 Feb 2012 17:27:56 -0500 Message-ID: <4F4C036A.2080808@zabbo.net> Date: Mon, 27 Feb 2012 17:27:54 -0500 From: Zach Brown User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0) Gecko/20120131 Thunderbird/10.0 MIME-Version: 1.0 To: Dave Kleikamp CC: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH 00/22] loop: Issue O_DIRECT aio with pages References: <1330377576-3659-1-git-send-email-dave.kleikamp@oracle.com> In-Reply-To: <1330377576-3659-1-git-send-email-dave.kleikamp@oracle.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1409 Lines: 31 On 02/27/2012 04:19 PM, Dave Kleikamp wrote: > This patchset was begun by Zach Brown and was originally submitted for > review in October, 2009. Man, it's been a while. I remembered almost none of the details of this work when I read your introductory message. As I read the patches it all came flooding back, though. Yikes :). My biggest fear about this patch series is the sheer amount of very fiddly code motion. I remember spending a lot of time verifying that the patches didn't accidentally lose new changes as the patches were ported to newer kernels. Has someone gone through these most recent patches with an absurdly fine toothed comb? The patches that touch fs/direct-io.c and mm/filemap.c are the most risky, by far. > This series was written to reduce the current overhead loop imposes by > performing synchronus buffered file system IO from a kernel thread. These > patches turn loop into a light weight layer that translates bios into iocbs. It'd be worth including some simple benchmark results, I think. I remember testing with concurrent O_DIRECT aio with fio on a loopback device on top of files in each underlying file system. - z -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/