From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262901AbTKJOfu (ORCPT ); Mon, 10 Nov 2003 09:35:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263039AbTKJOfu (ORCPT ); Mon, 10 Nov 2003 09:35:50 -0500 Received: from mail-10.iinet.net.au ([203.59.3.42]:54752 "HELO mail.iinet.net.au") by vger.kernel.org with SMTP id S262901AbTKJOfr (ORCPT ); Mon, 10 Nov 2003 09:35:47 -0500 Message-ID: <3FAFA1E8.8080800@cyberone.com.au> Date: Tue, 11 Nov 2003 01:34:16 +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> In-Reply-To: <20031110142302.GF32637@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: > >> >>Jens Axboe wrote: >> >> >>>Hi, >>> >>> >>> >>Hi Jens >> >> >>>@@ -1553,6 +1559,10 @@ >>> struct io_context *ioc = get_io_context(gfp_mask); >>> >>> spin_lock_irq(q->queue_lock); >>>+ >>>+ if (!elv_may_queue(q, rw)) >>>+ goto out_lock; >>>+ >>> if (rl->count[rw]+1 >= q->nr_requests) { >>> /* >>> * The queue will fill after this allocation, so set it as >>>@@ -1566,15 +1576,12 @@ >>> } >>> } >>> >>>- if (blk_queue_full(q, rw) >>>- && !ioc_batching(ioc) && !elv_may_queue(q, rw)) { >>> >>> >>I know I hijacked elv_may_queue from you... any chance we could seperate >>these so our schedulers can live in peace? ;) >> > >IOW, you completely broke it! I'm just changing it back to the >original. When was this done, btw? Just discovered it when updating the >patch. Pretty annoying... > You acked the change actually :P I guess it was done in mainline when AS was merged. > >>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).