From owner-freebsd-hackers@FreeBSD.ORG Tue Feb 5 20:43:55 2008 Return-Path: Delivered-To: freebsd-hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2643016A419; Tue, 5 Feb 2008 20:43:55 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.freebsd.org (Postfix) with ESMTP id AF62813C447; Tue, 5 Feb 2008 20:43:54 +0000 (UTC) (envelope-from scottl@samsco.org) Received: from phobos.samsco.home (phobos.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.13.8/8.13.8) with ESMTP id m15KhlRQ067518; Tue, 5 Feb 2008 13:43:48 -0700 (MST) (envelope-from scottl@samsco.org) Message-ID: <47A8CA83.1000405@samsco.org> Date: Tue, 05 Feb 2008 13:43:47 -0700 From: Scott Long User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.11) Gecko/20071128 SeaMonkey/1.1.7 MIME-Version: 1.0 To: Andriy Gapon References: <200612221824.kBMIOhfM049471@freefall.freebsd.org> <47A2EDB0.8000801@icyb.net.ua> <47A2F404.7010208@icyb.net.ua> <47A735A4.3060506@icyb.net.ua> <47A75B47.2040604@elischer.org> <1202155663.62432.0.camel@ikaros.oook.cz> <47A8754C.5010607@icyb.net.ua> In-Reply-To: <47A8754C.5010607@icyb.net.ua> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-1.4 required=5.4 tests=ALL_TRUSTED autolearn=failed version=3.1.8 X-Spam-Checker-Version: SpamAssassin 3.1.8 (2007-02-13) on pooker.samsco.org X-Mailman-Approved-At: Tue, 05 Feb 2008 20:48:46 +0000 Cc: Bruce Evans , freebsd-hackers@FreeBSD.org, scottl@FreeBSD.org, freebsd-fs@FreeBSD.org, pav@FreeBSD.org, Julian Elischer , Remko Lodder Subject: Re: fs/udf: vm pages "overlap" while reading large dir [patch] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Feb 2008 20:43:55 -0000 Andriy Gapon wrote: > on 04/02/2008 22:07 Pav Lucistnik said the following: >> Julian Elischer píše v po 04. 02. 2008 v 10:36 -0800: >>> Andriy Gapon wrote: >>>> More on the problem with reading big directories on UDF. >>> You do realise that you have now made yourself the official >>> maintainer of the UDF file system by submitting a competent >>> and insightful analysis of the problem? >> Yay, and can you fix the sequential read performance while you're at it? >> Kthx! >> > > Pav, > > this was almost trivial :-) > See the attached patch, first hunk is just for consistency. > The code was borrowed from cd9660, only field/variable names are adjusted. > Your patch looks reasonable. Btw, for the same reason that read-ahead makes file reading much faster, I would not change directory reading to be 1 sector at a time (unless you also do read-ahead for it). > But there is another issue that I also mentioned in the email about > directory reading. It is UDF_INVALID_BMAP case of udf_bmap_internal, > i.e. the case when file data is embedded into a file entry. > This is a special case that needs to be handled differently. > udf_readatoffset() handles it, but the latest udf_read code doesn't. > I have a real UDF filesystem where this type of allocation is used for > small files and those files can not be read. Oh, so directory data can also follow this convention? Blah. Feel free to fix that too if you want =-) Scott