From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751144AbWFBCeg (ORCPT ); Thu, 1 Jun 2006 22:34:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751146AbWFBCef (ORCPT ); Thu, 1 Jun 2006 22:34:35 -0400 Received: from smtp106.mail.mud.yahoo.com ([209.191.85.216]:48547 "HELO smtp106.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1751144AbWFBCef (ORCPT ); Thu, 1 Jun 2006 22:34:35 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=sirTGgeJ54/q/QtOUf7SuLbIa3lCwppBj0ZokHXT/oEEr2/bu7GL1dH1Uhe8JPjWGKbz7V5MkQBn1By6CKO9syI8YDjbm7qNzwWUlMd0Mip02B49n6jtPLA4bBVHiwuMnle2Ytd2tEhhE54TuT3nZqgDj4WPJxBeByNigx/oX34= ; Message-ID: <447FA3B3.7080407@yahoo.com.au> Date: Fri, 02 Jun 2006 12:34:27 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Linus Torvalds CC: linux-kernel@vger.kernel.org, axboe@suse.de Subject: Re: [rfc][patch] remove racy sync_page? References: <447AC011.8050708@yahoo.com.au> <20060529121556.349863b8.akpm@osdl.org> <447B8CE6.5000208@yahoo.com.au> <20060529183201.0e8173bc.akpm@osdl.org> <447BB3FD.1070707@yahoo.com.au> <447BD31E.7000503@yahoo.com.au> <447BD63D.2080900@yahoo.com.au> <447CE43A.6030700@yahoo.com.au> <447D9A41.8040601@yahoo.com.au> <447DAEDE.5070305@yahoo.com.au> <447DB765.6030702@yahoo.com.au> <447DC22C.5070503@yahoo.com.au> <447DC2CC.5060900@yahoo.com.au> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Linus Torvalds wrote: > > On Thu, 1 Jun 2006, Nick Piggin wrote: > >>If this wasn't clear: I don't mean per-task plugs as in "the task >>explicitly plugs and unplugs the block device"[*]; I mean really >>per-task plugs. > > > That would be insane. It would mean that you'd have to unplug whether you I don't think it is. > wanted to or not. Ie you've now made "sys_readahead()" impossible to do > well, and doing read-ahead across multiple files. Now it is you who are ignoring what I've been saying. I've been saying that I don't think your sys_readahead examples have had much to do with plugging: 1. If there are no other requests to seek to, plugging doesn't matter; 2. If there are other requests to seek to, the queue won't be plugged or will soon become unplugged anyway. So the current system isn't somehow going to do the right thing every time and be immune to seeking. > > You're ignoring all the _reasons_ for plugging in the first place. I'm not, but the current system of plugging isn't ideal. Anyway, there isn't any point going on about it, if I want to change anything I at least need to come back with numbers. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com