Messages in this thread |  | | Subject | Re: [PATCH v4 1/4] block: Add iocontext priority to request | From | Hannes Reinecke <> | Date | Sat, 15 Oct 2016 10:43:56 +0200 |
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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 <adam.manzanares@wdc.com> >>> --- >>> 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 <hare@suse.com>
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)
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