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deadline-iosched: Introduce dispatch helpers
Avoid directly referencing the next_rq and fifo_list arrays using the helper functions deadline_next_request() and deadline_fifo_request() to facilitate changes in the dispatch request selection in deadline_dispatch_requests() for zoned block devices. While at it, also remove the unnecessary forward declaration of the function deadline_move_request(). Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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c117bac701
1 changed files with 37 additions and 10 deletions
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@ -50,8 +50,6 @@ struct deadline_data {
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int front_merges;
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};
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static void deadline_move_request(struct deadline_data *, struct request *);
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static inline struct rb_root *
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deadline_rb_root(struct deadline_data *dd, struct request *rq)
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{
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@ -230,6 +228,35 @@ static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
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return 0;
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}
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/*
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* For the specified data direction, return the next request to dispatch using
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* arrival ordered lists.
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*/
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static struct request *
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deadline_fifo_request(struct deadline_data *dd, int data_dir)
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{
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if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
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return NULL;
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if (list_empty(&dd->fifo_list[data_dir]))
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return NULL;
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return rq_entry_fifo(dd->fifo_list[data_dir].next);
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}
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/*
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* For the specified data direction, return the next request to dispatch using
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* sector position sorted lists.
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*/
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static struct request *
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deadline_next_request(struct deadline_data *dd, int data_dir)
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{
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if (WARN_ON_ONCE(data_dir != READ && data_dir != WRITE))
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return NULL;
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return dd->next_rq[data_dir];
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}
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/*
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* deadline_dispatch_requests selects the best request according to
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* read/write expire, fifo_batch, etc
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@ -239,16 +266,15 @@ static int deadline_dispatch_requests(struct request_queue *q, int force)
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struct deadline_data *dd = q->elevator->elevator_data;
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const int reads = !list_empty(&dd->fifo_list[READ]);
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const int writes = !list_empty(&dd->fifo_list[WRITE]);
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struct request *rq;
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struct request *rq, *next_rq;
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int data_dir;
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/*
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* batches are currently reads XOR writes
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*/
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if (dd->next_rq[WRITE])
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rq = dd->next_rq[WRITE];
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else
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rq = dd->next_rq[READ];
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rq = deadline_next_request(dd, WRITE);
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if (!rq)
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rq = deadline_next_request(dd, READ);
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if (rq && dd->batching < dd->fifo_batch)
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/* we have a next request are still entitled to batch */
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@ -291,19 +317,20 @@ static int deadline_dispatch_requests(struct request_queue *q, int force)
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/*
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* we are not running a batch, find best request for selected data_dir
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*/
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if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) {
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next_rq = deadline_next_request(dd, data_dir);
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if (deadline_check_fifo(dd, data_dir) || !next_rq) {
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/*
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* A deadline has expired, the last request was in the other
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* direction, or we have run out of higher-sectored requests.
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* Start again from the request with the earliest expiry time.
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*/
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rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
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rq = deadline_fifo_request(dd, data_dir);
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} else {
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/*
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* The last req was the same dir and we have a next request in
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* sort order. No expired requests so continue on from here.
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*/
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rq = dd->next_rq[data_dir];
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rq = next_rq;
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}
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dd->batching = 0;
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