Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754339AbZJUQ12 (ORCPT ); Wed, 21 Oct 2009 12:27:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753675AbZJUQ11 (ORCPT ); Wed, 21 Oct 2009 12:27:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53707 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751725AbZJUQ11 convert rfc822-to-8bit (ORCPT ); Wed, 21 Oct 2009 12:27:27 -0400 From: Jeff Moyer To: Corrado Zoccolo Cc: Linux-Kernel , Jens Axboe Subject: Re: [RFC V2 PATCH 2/5] cfq-iosched: preparation to handle multiple service trees References: <200910202012.00196.czoccolo@gmail.com> <4e5e476b0910210925v7b44273flc22827d21fa1d6b9@mail.gmail.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Wed, 21 Oct 2009 12:27:26 -0400 In-Reply-To: <4e5e476b0910210925v7b44273flc22827d21fa1d6b9@mail.gmail.com> (Corrado Zoccolo's message of "Wed, 21 Oct 2009 18:25:47 +0200") Message-ID: User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1349 Lines: 38 Corrado Zoccolo writes: > Hi Jeff, > On Wed, Oct 21, 2009 at 5:31 PM, Jeff Moyer wrote: >> Corrado Zoccolo writes: >> >>> We embed a pointer to the service tree in each queue, to handle multiple >>> service trees easily. >>> Service trees are enriched with a counter. >>> cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure >>> that all fields in rq are properly initialized. >>> >>> @@ -115,6 +116,9 @@ struct cfq_queue { >>>       unsigned short ioprio_class, org_ioprio_class; >>> >>>       pid_t pid; >>> + >>> +     struct cfq_rb_root *service_tree; >>> +     struct cfq_io_context *cic; >>>  }; >> >> This change worries me.  For async queues, there is not a 1:1 mapping >> between cfqq and cic. > > Currently, I need it only for sync queues. And it is used only to > determine if a queue is seeky, so if we can mark it in the queue > instead of the cic, this will not be needed any more. Ah ha! I have the same requirement for breaking the queues apart, so I think this won't be an issue. Thanks! 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/