From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263866AbTKJOnT (ORCPT ); Mon, 10 Nov 2003 09:43:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263884AbTKJOnT (ORCPT ); Mon, 10 Nov 2003 09:43:19 -0500 Received: from mail-05.iinet.net.au ([203.59.3.37]:28570 "HELO mail.iinet.net.au") by vger.kernel.org with SMTP id S263866AbTKJOnR (ORCPT ); Mon, 10 Nov 2003 09:43:17 -0500 Message-ID: <3FAFA401.5080404@cyberone.com.au> Date: Tue, 11 Nov 2003 01:43:13 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030827 Debian/1.4-3 X-Accept-Language: en MIME-Version: 1.0 To: Jens Axboe CC: linux-kernel@vger.kernel.org, ckrm-tech@lists.sourceforge.net Subject: Re: [PATCH] cfq-prio #2 References: <20031110140052.GC32637@suse.de> <3FAF9DAE.3070307@cyberone.com.au> <20031110142302.GF32637@suse.de> <3FAFA1E8.8080800@cyberone.com.au> <20031110143939.GJ32637@suse.de> In-Reply-To: <20031110143939.GJ32637@suse.de> 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 Jens Axboe wrote: >On Tue, Nov 11 2003, Nick Piggin wrote: > >> >>You acked the change actually :P >>I guess it was done in mainline when AS was merged. >> > >Probably missed the semantic change of may_queue. > Anyway I won't bother digging up the email, its been done now. > >>>>Maybe my version should be called elv_force_queue? >>>> >>>> >>>I just hate to see more of these, really. The original idea for >>>may_queue was just that, may this process queue io or not. We can make >>>it return something else, though, to indicate whether the process must >>>be able to queue. Is it really needed? >>> >>> >>Its quite important. If the queue is full, and AS is waiting for a process >>to submit a request, its got a long wait. >> >>Maybe a lower limit for per process nr_requests. Ie. you may queue if this >>queue has less than 128 requests _or_ you have less than 8 requests >>outstanding. This would solve my problem. It would also give you a much more >>appropriate scaling for server workloads, I think. Still, thats quite a >>change in behaviour (simple to code though). >> > >That basically belongs inside your may_queue for the io scheduler, imo. > You can force it to disallow the request, but you can't force it to allow one (depending on a successful memory allocation, of course).