| Message ID | 20210618004456.7280-6-bvanassche@acm.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Improve I/O priority support | expand |
On Thu, Jun 17, 2021 at 05:44:45PM -0700, Bart Van Assche wrote: > Make the code easier to read by adding more comments. > > Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> > Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> > Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.de> > Cc: Ming Lei <ming.lei@redhat.com> > Signed-off-by: Bart Van Assche <bvanassche@acm.org> > --- > block/mq-deadline.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/block/mq-deadline.c b/block/mq-deadline.c > index 8eea2cbf2bf4..31418e9ce9e2 100644 > --- a/block/mq-deadline.c > +++ b/block/mq-deadline.c > @@ -139,6 +139,9 @@ static void dd_request_merged(struct request_queue *q, struct request *req, > } > } > > +/* > + * Callback function that is invoked after @next has been merged into @req. > + */ > static void dd_merged_requests(struct request_queue *q, struct request *req, > struct request *next) > { > @@ -375,6 +378,8 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd) > } > > /* > + * Called from blk_mq_run_hw_queue() -> __blk_mq_sched_dispatch_requests(). > + * > * One confusing aspect here is that we get called for a specific > * hardware queue, but we may return a request that is for a > * different hardware queue. This is because mq-deadline has shared > @@ -438,6 +443,10 @@ static int dd_init_queue(struct request_queue *q, struct elevator_type *e) > return 0; > } > > +/* > + * Try to merge @bio into an existing request. If @bio has been merged into > + * an existing request, store the pointer to that request into *@rq. > + */ > static int dd_request_merge(struct request_queue *q, struct request **rq, > struct bio *bio) > { > @@ -461,6 +470,10 @@ static int dd_request_merge(struct request_queue *q, struct request **rq, > return ELEVATOR_NO_MERGE; > } > > +/* > + * Attempt to merge a bio into an existing request. This function is called > + * before @bio is associated with a request. > + */ > static bool dd_bio_merge(struct request_queue *q, struct bio *bio, > unsigned int nr_segs) > { > @@ -518,6 +531,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, > } > } > > +/* > + * Called from blk_mq_sched_insert_request() or blk_mq_sched_insert_requests(). > + */ > static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, > struct list_head *list, bool at_head) > { > @@ -544,6 +560,8 @@ static void dd_prepare_request(struct request *rq) > } > > /* > + * Callback from inside blk_mq_free_request(). > + * > * For zoned block devices, write unlock the target zone of > * completed write requests. Do this while holding the zone lock > * spinlock so that the zone is never unlocked while deadline_fifo_request() Looks good. Reviewed by: Adam Manzanares <a.manzanares@samsung.com>
diff --git a/block/mq-deadline.c b/block/mq-deadline.c index 8eea2cbf2bf4..31418e9ce9e2 100644 --- a/block/mq-deadline.c +++ b/block/mq-deadline.c @@ -139,6 +139,9 @@ static void dd_request_merged(struct request_queue *q, struct request *req, } } +/* + * Callback function that is invoked after @next has been merged into @req. + */ static void dd_merged_requests(struct request_queue *q, struct request *req, struct request *next) { @@ -375,6 +378,8 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd) } /* + * Called from blk_mq_run_hw_queue() -> __blk_mq_sched_dispatch_requests(). + * * One confusing aspect here is that we get called for a specific * hardware queue, but we may return a request that is for a * different hardware queue. This is because mq-deadline has shared @@ -438,6 +443,10 @@ static int dd_init_queue(struct request_queue *q, struct elevator_type *e) return 0; } +/* + * Try to merge @bio into an existing request. If @bio has been merged into + * an existing request, store the pointer to that request into *@rq. + */ static int dd_request_merge(struct request_queue *q, struct request **rq, struct bio *bio) { @@ -461,6 +470,10 @@ static int dd_request_merge(struct request_queue *q, struct request **rq, return ELEVATOR_NO_MERGE; } +/* + * Attempt to merge a bio into an existing request. This function is called + * before @bio is associated with a request. + */ static bool dd_bio_merge(struct request_queue *q, struct bio *bio, unsigned int nr_segs) { @@ -518,6 +531,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, } } +/* + * Called from blk_mq_sched_insert_request() or blk_mq_sched_insert_requests(). + */ static void dd_insert_requests(struct blk_mq_hw_ctx *hctx, struct list_head *list, bool at_head) { @@ -544,6 +560,8 @@ static void dd_prepare_request(struct request *rq) } /* + * Callback from inside blk_mq_free_request(). + * * For zoned block devices, write unlock the target zone of * completed write requests. Do this while holding the zone lock * spinlock so that the zone is never unlocked while deadline_fifo_request()