Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753405AbcJMUKe (ORCPT ); Thu, 13 Oct 2016 16:10:34 -0400 Received: from mail-it0-f54.google.com ([209.85.214.54]:37254 "EHLO mail-it0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752376AbcJMUKA (ORCPT ); Thu, 13 Oct 2016 16:10:00 -0400 Subject: Re: [PATCH v4 1/4] block: Add iocontext priority to request To: Dan Williams , Adam Manzanares References: <1476388433-2539-1-git-send-email-adam.manzanares@hgst.com> <1476388433-2539-2-git-send-email-adam.manzanares@hgst.com> Cc: Tejun Heo , Hannes Reinecke , "Martin K. Petersen" , mchristi@redhat.com, Toshi Kani , Ming Lei , sathya.prakash@broadcom.com, chaitra.basappa@broadcom.com, suganath-prabu.subramani@broadcom.com, linux-block@vger.kernel.org, IDE/ATA development list , "linux-kernel@vger.kernel.org" , MPT-FusionLinux.pdl@broadcom.com, linux-scsi , Adam Manzananares From: Jens Axboe Message-ID: <068e03c4-3558-a6b1-2008-d13bde4958a1@kernel.dk> Date: Thu, 13 Oct 2016 14:09:34 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2017 Lines: 49 On 10/13/2016 02:06 PM, Dan Williams wrote: > On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares > wrote: >> Patch adds an association between iocontext ioprio and the ioprio of a >> request. This value is set in blk_rq_set_prio which takes the request and >> the ioc as arguments. If the ioc is valid in blk_rq_set_prio then the >> iopriority of the request is set as the iopriority of the ioc. In >> init_request_from_bio a check is made to see if the ioprio of the bio is >> valid and if so then the request prio comes from the bio. >> >> Signed-off-by: Adam Manzananares >> --- >> block/blk-core.c | 4 +++- >> include/linux/blkdev.h | 14 ++++++++++++++ >> 2 files changed, 17 insertions(+), 1 deletion(-) >> >> diff --git a/block/blk-core.c b/block/blk-core.c >> index 14d7c07..361b1b9 100644 >> --- a/block/blk-core.c >> +++ b/block/blk-core.c >> @@ -1153,6 +1153,7 @@ static struct request *__get_request(struct request_list *rl, int op, >> >> blk_rq_init(q, rq); >> blk_rq_set_rl(rq, rl); >> + blk_rq_set_prio(rq, ioc); >> req_set_op_attrs(rq, op, op_flags | REQ_ALLOCED); >> >> /* init elvpriv */ >> @@ -1656,7 +1657,8 @@ void init_request_from_bio(struct request *req, struct bio *bio) >> >> req->errors = 0; >> req->__sector = bio->bi_iter.bi_sector; >> - req->ioprio = bio_prio(bio); >> + if (ioprio_valid(bio_prio(bio))) >> + req->ioprio = bio_prio(bio); > > Should we use ioprio_best() here? If req->ioprio and bio_prio() > disagree one side has explicitly asked for a higher priority. It's a good question - but if priority has been set in the bio, it makes sense that that would take priority over the general setting for the task/io context. So I think the patch is correct as-is. Adam, you'll want to rewrite the commit message though. A good commit message should explain WHY the change is made, not detail the code implementation of it. -- Jens Axboe