Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753860AbcJOIo0 (ORCPT ); Sat, 15 Oct 2016 04:44:26 -0400 Received: from mx2.suse.de ([195.135.220.15]:47859 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753343AbcJOIoQ (ORCPT ); Sat, 15 Oct 2016 04:44:16 -0400 Subject: Re: [PATCH v4 1/4] block: Add iocontext priority to request To: Adam Manzananares References: <1476388433-2539-1-git-send-email-adam.manzanares@hgst.com> <1476388433-2539-2-git-send-email-adam.manzanares@hgst.com> <733629ac-fb98-9acf-3b2b-e1554e839346@suse.de> <20161014183554.GB6788@hgst.com> Cc: Adam Manzanares , axboe@kernel.dk, tj@kernel.org, dan.j.williams@intel.com, martin.petersen@oracle.com, mchristi@redhat.com, toshi.kani@hpe.com, ming.lei@canonical.com, sathya.prakash@broadcom.com, chaitra.basappa@broadcom.com, suganath-prabu.subramani@broadcom.com, linux-block@vger.kernel.org, linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, MPT-FusionLinux.pdl@broadcom.com, linux-scsi@vger.kernel.org From: Hannes Reinecke Message-ID: Date: Sat, 15 Oct 2016 10:43:56 +0200 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: <20161014183554.GB6788@hgst.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3218 Lines: 87 On 10/14/2016 08:35 PM, Adam Manzananares wrote: > The 10/14/2016 07:54, Hannes Reinecke wrote: >> On 10/13/2016 09:53 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); >>> blk_rq_bio_prep(req->q, req, bio); >>> } >>> >>> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >>> index c47c358..9a0ceaa 100644 >>> --- a/include/linux/blkdev.h >>> +++ b/include/linux/blkdev.h >>> @@ -934,6 +934,20 @@ static inline unsigned int blk_rq_count_bios(struct request *rq) >>> } >>> >>> /* >>> + * blk_rq_set_prio - associate a request with prio from ioc >>> + * @rq: request of interest >>> + * @ioc: target iocontext >>> + * >>> + * Assocate request prio with ioc prio so request based drivers >>> + * can leverage priority information. >>> + */ >>> +static inline void blk_rq_set_prio(struct request *rq, struct io_context *ioc) >>> +{ >>> + if (ioc) >>> + rq->ioprio = ioc->ioprio; >>> +} >>> + >>> +/* >>> * Request issue related functions. >>> */ >>> extern struct request *blk_peek_request(struct request_queue *q); >>> >> Don't you need to check for 'ioprio_valid()' here, too? > > I poked around and it should be safe to not check for ioprio valid > at this point. ioprio_valid only checks to see if the ioprio is > not IOPRIO_CLASS_NONE. The request by default has a ioprio of none > so if the ioc has ioprio of none we are not changing anything. > > The locations in the code that I found where the ioc prio is set are > either filtered through the syscall handler, which checks for invalid > priority combinations, or have valid priority values. > Thanks for the confirmation, that'll clarifies things. Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@suse.de +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)