On 10/13/2016 02:06 PM, Dan Williams wrote:
On Thu, Oct 13, 2016 at 12:53 PM, Adam Manzanares <adam.manzanares@xxxxxxxx> 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@xxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-block" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
