Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264162AbUDGTms (ORCPT ); Wed, 7 Apr 2004 15:42:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264173AbUDGTms (ORCPT ); Wed, 7 Apr 2004 15:42:48 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:57572 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S264162AbUDGTmr (ORCPT ); Wed, 7 Apr 2004 15:42:47 -0400 Message-ID: <407459A2.4030009@pobox.com> Date: Wed, 07 Apr 2004 15:42:26 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Miller, Mike (OS Dev)" CC: akpm@odsl.org, axboe@suse.de, linux-kernel@vger.kernel.org Subject: Re: cciss updates for 2.6.6xxx [1/2] References: 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 Content-Length: 1166 Lines: 26 Miller, Mike (OS Dev) wrote: > I like the idea of capping max commands based on the number of arrays. One problem is that we can add or remove a logical drive during runtime. How would Linux handle us reshuffling the max commands for each queue? What is the maximum number of logical drives? If you always assume the maximum number of logical drives are configured (let's say 32), then you can calculate based on that: 1024 / 32 logical drives == 32 commands per logical drive It certainly gets a bit more complex, if you truly want to handle something other than "hardcode max # of logical drives"... I would suggest going to a round-robin anti-starvation approach at that point, like what I do in carmel.c. The Carmel hardware has a single hardware queue for all of its 8 SATA ports, which is similar to cciss having 1024 commands for all of its logical drives (if I understand things correctly). Jeff - 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/