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	blk-rq-qos: refactor out common elements of blk-wbt
blkcg-qos is going to do essentially what wbt does, only on a cgroup basis. Break out the common code that will be shared between blkcg-qos and wbt into blk-rq-qos.* so they can both utilize the same infrastructure. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
		
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									2ecbf45635
								
							
						
					
					
						commit
						a79050434b
					
				
					 10 changed files with 480 additions and 253 deletions
				
			
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			@ -9,7 +9,7 @@ obj-$(CONFIG_BLOCK) := bio.o elevator.o blk-core.o blk-tag.o blk-sysfs.o \
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			blk-lib.o blk-mq.o blk-mq-tag.o blk-stat.o \
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			blk-mq-sysfs.o blk-mq-cpumap.o blk-mq-sched.o ioctl.o \
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			genhd.o partition-generic.o ioprio.o \
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			badblocks.o partitions/
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			badblocks.o partitions/ blk-rq-qos.o
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obj-$(CONFIG_BOUNCE)		+= bounce.o
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obj-$(CONFIG_BLK_SCSI_REQUEST)	+= scsi_ioctl.o
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			@ -1645,7 +1645,7 @@ void blk_requeue_request(struct request_queue *q, struct request *rq)
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	blk_delete_timer(rq);
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	blk_clear_rq_complete(rq);
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	trace_block_rq_requeue(q, rq);
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	wbt_requeue(q->rq_wb, rq);
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	rq_qos_requeue(q, rq);
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	if (rq->rq_flags & RQF_QUEUED)
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		blk_queue_end_tag(q, rq);
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			@ -1752,7 +1752,7 @@ void __blk_put_request(struct request_queue *q, struct request *req)
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	/* this is a bio leak */
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	WARN_ON(req->bio != NULL);
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	wbt_done(q->rq_wb, req);
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	rq_qos_done(q, req);
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	/*
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	 * Request may not have originated from ll_rw_blk. if not,
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			@ -2044,7 +2044,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
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	}
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get_rq:
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	wb_acct = wbt_wait(q->rq_wb, bio, q->queue_lock);
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	wb_acct = rq_qos_throttle(q, bio, q->queue_lock);
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	/*
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	 * Grab a free request. This is might sleep but can not fail.
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			@ -2054,7 +2054,7 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio)
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	req = get_request(q, bio->bi_opf, bio, 0, GFP_NOIO);
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	if (IS_ERR(req)) {
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		blk_queue_exit(q);
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		__wbt_done(q->rq_wb, wb_acct);
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		rq_qos_cleanup(q, wb_acct);
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		if (PTR_ERR(req) == -ENOMEM)
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			bio->bi_status = BLK_STS_RESOURCE;
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		else
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			@ -2983,7 +2983,7 @@ void blk_start_request(struct request *req)
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		req->throtl_size = blk_rq_sectors(req);
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#endif
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		req->rq_flags |= RQF_STATS;
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		wbt_issue(req->q->rq_wb, req);
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		rq_qos_issue(req->q, req);
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	}
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	BUG_ON(blk_rq_is_complete(req));
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			@ -3207,7 +3207,7 @@ void blk_finish_request(struct request *req, blk_status_t error)
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	blk_account_io_done(req, now);
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	if (req->end_io) {
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		wbt_done(req->q->rq_wb, req);
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		rq_qos_done(q, req);
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		req->end_io(req, error);
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	} else {
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		if (blk_bidi_rq(req))
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			@ -504,7 +504,7 @@ void blk_mq_free_request(struct request *rq)
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	if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
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		laptop_io_completion(q->backing_dev_info);
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	wbt_done(q->rq_wb, rq);
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	rq_qos_done(q, rq);
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	if (blk_rq_rl(rq))
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		blk_put_rl(blk_rq_rl(rq));
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			@ -527,7 +527,7 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
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	blk_account_io_done(rq, now);
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	if (rq->end_io) {
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		wbt_done(rq->q->rq_wb, rq);
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		rq_qos_done(rq->q, rq);
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		rq->end_io(rq, error);
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	} else {
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		if (unlikely(blk_bidi_rq(rq)))
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			@ -641,7 +641,7 @@ void blk_mq_start_request(struct request *rq)
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		rq->throtl_size = blk_rq_sectors(rq);
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#endif
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		rq->rq_flags |= RQF_STATS;
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		wbt_issue(q->rq_wb, rq);
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		rq_qos_issue(q, rq);
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	}
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	WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
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			@ -667,7 +667,7 @@ static void __blk_mq_requeue_request(struct request *rq)
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	blk_mq_put_driver_tag(rq);
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	trace_block_rq_requeue(q, rq);
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	wbt_requeue(q->rq_wb, rq);
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	rq_qos_requeue(q, rq);
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	if (blk_mq_request_started(rq)) {
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		WRITE_ONCE(rq->state, MQ_RQ_IDLE);
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			@ -1806,13 +1806,13 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
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	if (blk_mq_sched_bio_merge(q, bio))
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		return BLK_QC_T_NONE;
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	wb_acct = wbt_wait(q->rq_wb, bio, NULL);
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	wb_acct = rq_qos_throttle(q, bio, NULL);
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	trace_block_getrq(q, bio, bio->bi_opf);
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	rq = blk_mq_get_request(q, bio, bio->bi_opf, &data);
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	if (unlikely(!rq)) {
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		__wbt_done(q->rq_wb, wb_acct);
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		rq_qos_cleanup(q, wb_acct);
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		if (bio->bi_opf & REQ_NOWAIT)
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			bio_wouldblock_error(bio);
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		return BLK_QC_T_NONE;
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										178
									
								
								block/blk-rq-qos.c
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										178
									
								
								block/blk-rq-qos.c
									
									
									
									
									
										Normal file
									
								
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			@ -0,0 +1,178 @@
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#include "blk-rq-qos.h"
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#include "blk-wbt.h"
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/*
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 * Increment 'v', if 'v' is below 'below'. Returns true if we succeeded,
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 * false if 'v' + 1 would be bigger than 'below'.
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 */
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static bool atomic_inc_below(atomic_t *v, int below)
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{
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	int cur = atomic_read(v);
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	for (;;) {
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		int old;
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		if (cur >= below)
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			return false;
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		old = atomic_cmpxchg(v, cur, cur + 1);
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		if (old == cur)
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			break;
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		cur = old;
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	}
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	return true;
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}
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bool rq_wait_inc_below(struct rq_wait *rq_wait, int limit)
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{
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	return atomic_inc_below(&rq_wait->inflight, limit);
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}
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void rq_qos_cleanup(struct request_queue *q, enum wbt_flags wb_acct)
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{
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	struct rq_qos *rqos;
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	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
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		if (rqos->ops->cleanup)
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			rqos->ops->cleanup(rqos, wb_acct);
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	}
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}
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void rq_qos_done(struct request_queue *q, struct request *rq)
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{
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	struct rq_qos *rqos;
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	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
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		if (rqos->ops->done)
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			rqos->ops->done(rqos, rq);
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	}
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}
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void rq_qos_issue(struct request_queue *q, struct request *rq)
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{
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	struct rq_qos *rqos;
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	for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
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		if (rqos->ops->issue)
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			rqos->ops->issue(rqos, rq);
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	}
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}
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void rq_qos_requeue(struct request_queue *q, struct request *rq)
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{
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	struct rq_qos *rqos;
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	for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
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		if (rqos->ops->requeue)
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			rqos->ops->requeue(rqos, rq);
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	}
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}
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enum wbt_flags rq_qos_throttle(struct request_queue *q, struct bio *bio,
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			       spinlock_t *lock)
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{
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	struct rq_qos *rqos;
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	enum wbt_flags flags = 0;
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	for(rqos = q->rq_qos; rqos; rqos = rqos->next) {
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		if (rqos->ops->throttle)
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			flags |= rqos->ops->throttle(rqos, bio, lock);
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	}
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	return flags;
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}
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/*
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 * Return true, if we can't increase the depth further by scaling
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 */
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bool rq_depth_calc_max_depth(struct rq_depth *rqd)
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{
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	unsigned int depth;
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	bool ret = false;
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	/*
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	 * For QD=1 devices, this is a special case. It's important for those
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	 * to have one request ready when one completes, so force a depth of
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	 * 2 for those devices. On the backend, it'll be a depth of 1 anyway,
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	 * since the device can't have more than that in flight. If we're
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	 * scaling down, then keep a setting of 1/1/1.
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	 */
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	if (rqd->queue_depth == 1) {
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		if (rqd->scale_step > 0)
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			rqd->max_depth = 1;
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		else {
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			rqd->max_depth = 2;
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			ret = true;
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		}
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	} else {
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		/*
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		 * scale_step == 0 is our default state. If we have suffered
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		 * latency spikes, step will be > 0, and we shrink the
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		 * allowed write depths. If step is < 0, we're only doing
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		 * writes, and we allow a temporarily higher depth to
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		 * increase performance.
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		 */
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		depth = min_t(unsigned int, rqd->default_depth,
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			      rqd->queue_depth);
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		if (rqd->scale_step > 0)
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			depth = 1 + ((depth - 1) >> min(31, rqd->scale_step));
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		else if (rqd->scale_step < 0) {
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			unsigned int maxd = 3 * rqd->queue_depth / 4;
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			depth = 1 + ((depth - 1) << -rqd->scale_step);
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			if (depth > maxd) {
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				depth = maxd;
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				ret = true;
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			}
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		}
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		rqd->max_depth = depth;
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	}
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	return ret;
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}
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void rq_depth_scale_up(struct rq_depth *rqd)
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{
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	/*
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	 * Hit max in previous round, stop here
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	 */
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	if (rqd->scaled_max)
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		return;
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	rqd->scale_step--;
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	rqd->scaled_max = rq_depth_calc_max_depth(rqd);
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}
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/*
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 * Scale rwb down. If 'hard_throttle' is set, do it quicker, since we
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 * had a latency violation.
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 */
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void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle)
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{
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	/*
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	 * Stop scaling down when we've hit the limit. This also prevents
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	 * ->scale_step from going to crazy values, if the device can't
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	 * keep up.
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	 */
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	if (rqd->max_depth == 1)
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		return;
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	if (rqd->scale_step < 0 && hard_throttle)
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		rqd->scale_step = 0;
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	else
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		rqd->scale_step++;
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	rqd->scaled_max = false;
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	rq_depth_calc_max_depth(rqd);
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}
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void rq_qos_exit(struct request_queue *q)
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{
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	while (q->rq_qos) {
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		struct rq_qos *rqos = q->rq_qos;
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		q->rq_qos = rqos->next;
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		rqos->ops->exit(rqos);
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	}
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}
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		||||
							
								
								
									
										106
									
								
								block/blk-rq-qos.h
									
									
									
									
									
										Normal file
									
								
							
							
						
						
									
										106
									
								
								block/blk-rq-qos.h
									
									
									
									
									
										Normal file
									
								
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			@ -0,0 +1,106 @@
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#ifndef RQ_QOS_H
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#define RQ_QOS_H
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#include <linux/kernel.h>
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#include <linux/blkdev.h>
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#include <linux/blk_types.h>
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#include <linux/atomic.h>
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#include <linux/wait.h>
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enum rq_qos_id {
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	RQ_QOS_WBT,
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	RQ_QOS_CGROUP,
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};
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struct rq_wait {
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	wait_queue_head_t wait;
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	atomic_t inflight;
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};
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struct rq_qos {
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	struct rq_qos_ops *ops;
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	struct request_queue *q;
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	enum rq_qos_id id;
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	struct rq_qos *next;
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};
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struct rq_qos_ops {
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	enum wbt_flags (*throttle)(struct rq_qos *, struct bio *,
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				   spinlock_t *);
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	void (*issue)(struct rq_qos *, struct request *);
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	void (*requeue)(struct rq_qos *, struct request *);
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	void (*done)(struct rq_qos *, struct request *);
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	void (*cleanup)(struct rq_qos *, enum wbt_flags);
 | 
			
		||||
	void (*exit)(struct rq_qos *);
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
struct rq_depth {
 | 
			
		||||
	unsigned int max_depth;
 | 
			
		||||
 | 
			
		||||
	int scale_step;
 | 
			
		||||
	bool scaled_max;
 | 
			
		||||
 | 
			
		||||
	unsigned int queue_depth;
 | 
			
		||||
	unsigned int default_depth;
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
static inline struct rq_qos *rq_qos_id(struct request_queue *q,
 | 
			
		||||
				       enum rq_qos_id id)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos;
 | 
			
		||||
	for (rqos = q->rq_qos; rqos; rqos = rqos->next) {
 | 
			
		||||
		if (rqos->id == id)
 | 
			
		||||
			break;
 | 
			
		||||
	}
 | 
			
		||||
	return rqos;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	return rq_qos_id(q, RQ_QOS_WBT);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	return rq_qos_id(q, RQ_QOS_CGROUP);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline void rq_wait_init(struct rq_wait *rq_wait)
 | 
			
		||||
{
 | 
			
		||||
	atomic_set(&rq_wait->inflight, 0);
 | 
			
		||||
	init_waitqueue_head(&rq_wait->wait);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline void rq_qos_add(struct request_queue *q, struct rq_qos *rqos)
 | 
			
		||||
{
 | 
			
		||||
	rqos->next = q->rq_qos;
 | 
			
		||||
	q->rq_qos = rqos;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline void rq_qos_del(struct request_queue *q, struct rq_qos *rqos)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *cur, *prev = NULL;
 | 
			
		||||
	for (cur = q->rq_qos; cur; cur = cur->next) {
 | 
			
		||||
		if (cur == rqos) {
 | 
			
		||||
			if (prev)
 | 
			
		||||
				prev->next = rqos->next;
 | 
			
		||||
			else
 | 
			
		||||
				q->rq_qos = cur;
 | 
			
		||||
			break;
 | 
			
		||||
		}
 | 
			
		||||
		prev = cur;
 | 
			
		||||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
bool rq_wait_inc_below(struct rq_wait *rq_wait, int limit);
 | 
			
		||||
void rq_depth_scale_up(struct rq_depth *rqd);
 | 
			
		||||
void rq_depth_scale_down(struct rq_depth *rqd, bool hard_throttle);
 | 
			
		||||
bool rq_depth_calc_max_depth(struct rq_depth *rqd);
 | 
			
		||||
 | 
			
		||||
void rq_qos_cleanup(struct request_queue *, enum wbt_flags);
 | 
			
		||||
void rq_qos_done(struct request_queue *, struct request *);
 | 
			
		||||
void rq_qos_issue(struct request_queue *, struct request *);
 | 
			
		||||
void rq_qos_requeue(struct request_queue *, struct request *);
 | 
			
		||||
enum wbt_flags rq_qos_throttle(struct request_queue *, struct bio *, spinlock_t *);
 | 
			
		||||
void rq_qos_exit(struct request_queue *);
 | 
			
		||||
#endif
 | 
			
		||||
| 
						 | 
				
			
			@ -875,7 +875,7 @@ EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
 | 
			
		|||
void blk_set_queue_depth(struct request_queue *q, unsigned int depth)
 | 
			
		||||
{
 | 
			
		||||
	q->queue_depth = depth;
 | 
			
		||||
	wbt_set_queue_depth(q->rq_wb, depth);
 | 
			
		||||
	wbt_set_queue_depth(q, depth);
 | 
			
		||||
}
 | 
			
		||||
EXPORT_SYMBOL(blk_set_queue_depth);
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -900,7 +900,7 @@ void blk_queue_write_cache(struct request_queue *q, bool wc, bool fua)
 | 
			
		|||
		queue_flag_clear(QUEUE_FLAG_FUA, q);
 | 
			
		||||
	spin_unlock_irq(q->queue_lock);
 | 
			
		||||
 | 
			
		||||
	wbt_set_write_cache(q->rq_wb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 | 
			
		||||
	wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 | 
			
		||||
}
 | 
			
		||||
EXPORT_SYMBOL_GPL(blk_queue_write_cache);
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
| 
						 | 
				
			
			@ -422,16 +422,16 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page,
 | 
			
		|||
 | 
			
		||||
static ssize_t queue_wb_lat_show(struct request_queue *q, char *page)
 | 
			
		||||
{
 | 
			
		||||
	if (!q->rq_wb)
 | 
			
		||||
	if (!wbt_rq_qos(q))
 | 
			
		||||
		return -EINVAL;
 | 
			
		||||
 | 
			
		||||
	return sprintf(page, "%llu\n", div_u64(q->rq_wb->min_lat_nsec, 1000));
 | 
			
		||||
	return sprintf(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000));
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 | 
			
		||||
				  size_t count)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb;
 | 
			
		||||
	struct rq_qos *rqos;
 | 
			
		||||
	ssize_t ret;
 | 
			
		||||
	s64 val;
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -441,23 +441,21 @@ static ssize_t queue_wb_lat_store(struct request_queue *q, const char *page,
 | 
			
		|||
	if (val < -1)
 | 
			
		||||
		return -EINVAL;
 | 
			
		||||
 | 
			
		||||
	rwb = q->rq_wb;
 | 
			
		||||
	if (!rwb) {
 | 
			
		||||
	rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (!rqos) {
 | 
			
		||||
		ret = wbt_init(q);
 | 
			
		||||
		if (ret)
 | 
			
		||||
			return ret;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	rwb = q->rq_wb;
 | 
			
		||||
	if (val == -1)
 | 
			
		||||
		rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 | 
			
		||||
		val = wbt_default_latency_nsec(q);
 | 
			
		||||
	else if (val >= 0)
 | 
			
		||||
		rwb->min_lat_nsec = val * 1000ULL;
 | 
			
		||||
		val *= 1000ULL;
 | 
			
		||||
 | 
			
		||||
	if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
 | 
			
		||||
		rwb->enable_state = WBT_STATE_ON_MANUAL;
 | 
			
		||||
	wbt_set_min_lat(q, val);
 | 
			
		||||
 | 
			
		||||
	wbt_update_limits(rwb);
 | 
			
		||||
	wbt_update_limits(q);
 | 
			
		||||
	return count;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -964,7 +962,7 @@ void blk_unregister_queue(struct gendisk *disk)
 | 
			
		|||
	kobject_del(&q->kobj);
 | 
			
		||||
	blk_trace_remove_sysfs(disk_to_dev(disk));
 | 
			
		||||
 | 
			
		||||
	wbt_exit(q);
 | 
			
		||||
	rq_qos_exit(q);
 | 
			
		||||
 | 
			
		||||
	mutex_lock(&q->sysfs_lock);
 | 
			
		||||
	if (q->request_fn || (q->mq_ops && q->elevator))
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
							
								
								
									
										326
									
								
								block/blk-wbt.c
									
									
									
									
									
								
							
							
						
						
									
										326
									
								
								block/blk-wbt.c
									
									
									
									
									
								
							| 
						 | 
				
			
			@ -25,6 +25,7 @@
 | 
			
		|||
#include <linux/swap.h>
 | 
			
		||||
 | 
			
		||||
#include "blk-wbt.h"
 | 
			
		||||
#include "blk-rq-qos.h"
 | 
			
		||||
 | 
			
		||||
#define CREATE_TRACE_POINTS
 | 
			
		||||
#include <trace/events/wbt.h>
 | 
			
		||||
| 
						 | 
				
			
			@ -78,28 +79,6 @@ static inline bool rwb_enabled(struct rq_wb *rwb)
 | 
			
		|||
	return rwb && rwb->wb_normal != 0;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Increment 'v', if 'v' is below 'below'. Returns true if we succeeded,
 | 
			
		||||
 * false if 'v' + 1 would be bigger than 'below'.
 | 
			
		||||
 */
 | 
			
		||||
static bool atomic_inc_below(atomic_t *v, int below)
 | 
			
		||||
{
 | 
			
		||||
	int cur = atomic_read(v);
 | 
			
		||||
 | 
			
		||||
	for (;;) {
 | 
			
		||||
		int old;
 | 
			
		||||
 | 
			
		||||
		if (cur >= below)
 | 
			
		||||
			return false;
 | 
			
		||||
		old = atomic_cmpxchg(v, cur, cur + 1);
 | 
			
		||||
		if (old == cur)
 | 
			
		||||
			break;
 | 
			
		||||
		cur = old;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	return true;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
 | 
			
		||||
{
 | 
			
		||||
	if (rwb_enabled(rwb)) {
 | 
			
		||||
| 
						 | 
				
			
			@ -116,7 +95,7 @@ static void wb_timestamp(struct rq_wb *rwb, unsigned long *var)
 | 
			
		|||
 */
 | 
			
		||||
static bool wb_recent_wait(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	struct bdi_writeback *wb = &rwb->queue->backing_dev_info->wb;
 | 
			
		||||
	struct bdi_writeback *wb = &rwb->rqos.q->backing_dev_info->wb;
 | 
			
		||||
 | 
			
		||||
	return time_before(jiffies, wb->dirty_sleep + HZ);
 | 
			
		||||
}
 | 
			
		||||
| 
						 | 
				
			
			@ -144,8 +123,9 @@ static void rwb_wake_all(struct rq_wb *rwb)
 | 
			
		|||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct)
 | 
			
		||||
static void __wbt_done(struct rq_qos *rqos, enum wbt_flags wb_acct)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
	struct rq_wait *rqw;
 | 
			
		||||
	int inflight, limit;
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -194,10 +174,9 @@ void __wbt_done(struct rq_wb *rwb, enum wbt_flags wb_acct)
 | 
			
		|||
 * Called on completion of a request. Note that it's also called when
 | 
			
		||||
 * a request is merged, when the request gets freed.
 | 
			
		||||
 */
 | 
			
		||||
void wbt_done(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
static void wbt_done(struct rq_qos *rqos, struct request *rq)
 | 
			
		||||
{
 | 
			
		||||
	if (!rwb)
 | 
			
		||||
		return;
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
 | 
			
		||||
	if (!wbt_is_tracked(rq)) {
 | 
			
		||||
		if (rwb->sync_cookie == rq) {
 | 
			
		||||
| 
						 | 
				
			
			@ -209,72 +188,11 @@ void wbt_done(struct rq_wb *rwb, struct request *rq)
 | 
			
		|||
			wb_timestamp(rwb, &rwb->last_comp);
 | 
			
		||||
	} else {
 | 
			
		||||
		WARN_ON_ONCE(rq == rwb->sync_cookie);
 | 
			
		||||
		__wbt_done(rwb, wbt_flags(rq));
 | 
			
		||||
		__wbt_done(rqos, wbt_flags(rq));
 | 
			
		||||
	}
 | 
			
		||||
	wbt_clear_state(rq);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Return true, if we can't increase the depth further by scaling
 | 
			
		||||
 */
 | 
			
		||||
static bool calc_wb_limits(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	unsigned int depth;
 | 
			
		||||
	bool ret = false;
 | 
			
		||||
 | 
			
		||||
	if (!rwb->min_lat_nsec) {
 | 
			
		||||
		rwb->wb_max = rwb->wb_normal = rwb->wb_background = 0;
 | 
			
		||||
		return false;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	/*
 | 
			
		||||
	 * For QD=1 devices, this is a special case. It's important for those
 | 
			
		||||
	 * to have one request ready when one completes, so force a depth of
 | 
			
		||||
	 * 2 for those devices. On the backend, it'll be a depth of 1 anyway,
 | 
			
		||||
	 * since the device can't have more than that in flight. If we're
 | 
			
		||||
	 * scaling down, then keep a setting of 1/1/1.
 | 
			
		||||
	 */
 | 
			
		||||
	if (rwb->queue_depth == 1) {
 | 
			
		||||
		if (rwb->scale_step > 0)
 | 
			
		||||
			rwb->wb_max = rwb->wb_normal = 1;
 | 
			
		||||
		else {
 | 
			
		||||
			rwb->wb_max = rwb->wb_normal = 2;
 | 
			
		||||
			ret = true;
 | 
			
		||||
		}
 | 
			
		||||
		rwb->wb_background = 1;
 | 
			
		||||
	} else {
 | 
			
		||||
		/*
 | 
			
		||||
		 * scale_step == 0 is our default state. If we have suffered
 | 
			
		||||
		 * latency spikes, step will be > 0, and we shrink the
 | 
			
		||||
		 * allowed write depths. If step is < 0, we're only doing
 | 
			
		||||
		 * writes, and we allow a temporarily higher depth to
 | 
			
		||||
		 * increase performance.
 | 
			
		||||
		 */
 | 
			
		||||
		depth = min_t(unsigned int, RWB_DEF_DEPTH, rwb->queue_depth);
 | 
			
		||||
		if (rwb->scale_step > 0)
 | 
			
		||||
			depth = 1 + ((depth - 1) >> min(31, rwb->scale_step));
 | 
			
		||||
		else if (rwb->scale_step < 0) {
 | 
			
		||||
			unsigned int maxd = 3 * rwb->queue_depth / 4;
 | 
			
		||||
 | 
			
		||||
			depth = 1 + ((depth - 1) << -rwb->scale_step);
 | 
			
		||||
			if (depth > maxd) {
 | 
			
		||||
				depth = maxd;
 | 
			
		||||
				ret = true;
 | 
			
		||||
			}
 | 
			
		||||
		}
 | 
			
		||||
 | 
			
		||||
		/*
 | 
			
		||||
		 * Set our max/normal/bg queue depths based on how far
 | 
			
		||||
		 * we have scaled down (->scale_step).
 | 
			
		||||
		 */
 | 
			
		||||
		rwb->wb_max = depth;
 | 
			
		||||
		rwb->wb_normal = (rwb->wb_max + 1) / 2;
 | 
			
		||||
		rwb->wb_background = (rwb->wb_max + 3) / 4;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	return ret;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline bool stat_sample_valid(struct blk_rq_stat *stat)
 | 
			
		||||
{
 | 
			
		||||
	/*
 | 
			
		||||
| 
						 | 
				
			
			@ -307,7 +225,8 @@ enum {
 | 
			
		|||
 | 
			
		||||
static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
 | 
			
		||||
{
 | 
			
		||||
	struct backing_dev_info *bdi = rwb->queue->backing_dev_info;
 | 
			
		||||
	struct backing_dev_info *bdi = rwb->rqos.q->backing_dev_info;
 | 
			
		||||
	struct rq_depth *rqd = &rwb->rq_depth;
 | 
			
		||||
	u64 thislat;
 | 
			
		||||
 | 
			
		||||
	/*
 | 
			
		||||
| 
						 | 
				
			
			@ -351,7 +270,7 @@ static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
 | 
			
		|||
		return LAT_EXCEEDED;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	if (rwb->scale_step)
 | 
			
		||||
	if (rqd->scale_step)
 | 
			
		||||
		trace_wbt_stat(bdi, stat);
 | 
			
		||||
 | 
			
		||||
	return LAT_OK;
 | 
			
		||||
| 
						 | 
				
			
			@ -359,58 +278,48 @@ static int latency_exceeded(struct rq_wb *rwb, struct blk_rq_stat *stat)
 | 
			
		|||
 | 
			
		||||
static void rwb_trace_step(struct rq_wb *rwb, const char *msg)
 | 
			
		||||
{
 | 
			
		||||
	struct backing_dev_info *bdi = rwb->queue->backing_dev_info;
 | 
			
		||||
	struct backing_dev_info *bdi = rwb->rqos.q->backing_dev_info;
 | 
			
		||||
	struct rq_depth *rqd = &rwb->rq_depth;
 | 
			
		||||
 | 
			
		||||
	trace_wbt_step(bdi, msg, rwb->scale_step, rwb->cur_win_nsec,
 | 
			
		||||
			rwb->wb_background, rwb->wb_normal, rwb->wb_max);
 | 
			
		||||
	trace_wbt_step(bdi, msg, rqd->scale_step, rwb->cur_win_nsec,
 | 
			
		||||
			rwb->wb_background, rwb->wb_normal, rqd->max_depth);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static void calc_wb_limits(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	if (rwb->min_lat_nsec == 0) {
 | 
			
		||||
		rwb->wb_normal = rwb->wb_background = 0;
 | 
			
		||||
	} else if (rwb->rq_depth.max_depth <= 2) {
 | 
			
		||||
		rwb->wb_normal = rwb->rq_depth.max_depth;
 | 
			
		||||
		rwb->wb_background = 1;
 | 
			
		||||
	} else {
 | 
			
		||||
		rwb->wb_normal = (rwb->rq_depth.max_depth + 1) / 2;
 | 
			
		||||
		rwb->wb_background = (rwb->rq_depth.max_depth + 3) / 4;
 | 
			
		||||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static void scale_up(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	/*
 | 
			
		||||
	 * Hit max in previous round, stop here
 | 
			
		||||
	 */
 | 
			
		||||
	if (rwb->scaled_max)
 | 
			
		||||
		return;
 | 
			
		||||
 | 
			
		||||
	rwb->scale_step--;
 | 
			
		||||
	rq_depth_scale_up(&rwb->rq_depth);
 | 
			
		||||
	calc_wb_limits(rwb);
 | 
			
		||||
	rwb->unknown_cnt = 0;
 | 
			
		||||
 | 
			
		||||
	rwb->scaled_max = calc_wb_limits(rwb);
 | 
			
		||||
 | 
			
		||||
	rwb_wake_all(rwb);
 | 
			
		||||
 | 
			
		||||
	rwb_trace_step(rwb, "step up");
 | 
			
		||||
	rwb_trace_step(rwb, "scale up");
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Scale rwb down. If 'hard_throttle' is set, do it quicker, since we
 | 
			
		||||
 * had a latency violation.
 | 
			
		||||
 */
 | 
			
		||||
static void scale_down(struct rq_wb *rwb, bool hard_throttle)
 | 
			
		||||
{
 | 
			
		||||
	/*
 | 
			
		||||
	 * Stop scaling down when we've hit the limit. This also prevents
 | 
			
		||||
	 * ->scale_step from going to crazy values, if the device can't
 | 
			
		||||
	 * keep up.
 | 
			
		||||
	 */
 | 
			
		||||
	if (rwb->wb_max == 1)
 | 
			
		||||
		return;
 | 
			
		||||
 | 
			
		||||
	if (rwb->scale_step < 0 && hard_throttle)
 | 
			
		||||
		rwb->scale_step = 0;
 | 
			
		||||
	else
 | 
			
		||||
		rwb->scale_step++;
 | 
			
		||||
 | 
			
		||||
	rwb->scaled_max = false;
 | 
			
		||||
	rwb->unknown_cnt = 0;
 | 
			
		||||
	rq_depth_scale_down(&rwb->rq_depth, hard_throttle);
 | 
			
		||||
	calc_wb_limits(rwb);
 | 
			
		||||
	rwb_trace_step(rwb, "step down");
 | 
			
		||||
	rwb->unknown_cnt = 0;
 | 
			
		||||
	rwb_wake_all(rwb);
 | 
			
		||||
	rwb_trace_step(rwb, "scale down");
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static void rwb_arm_timer(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	if (rwb->scale_step > 0) {
 | 
			
		||||
	struct rq_depth *rqd = &rwb->rq_depth;
 | 
			
		||||
 | 
			
		||||
	if (rqd->scale_step > 0) {
 | 
			
		||||
		/*
 | 
			
		||||
		 * We should speed this up, using some variant of a fast
 | 
			
		||||
		 * integer inverse square root calculation. Since we only do
 | 
			
		||||
| 
						 | 
				
			
			@ -418,7 +327,7 @@ static void rwb_arm_timer(struct rq_wb *rwb)
 | 
			
		|||
		 * though.
 | 
			
		||||
		 */
 | 
			
		||||
		rwb->cur_win_nsec = div_u64(rwb->win_nsec << 4,
 | 
			
		||||
					int_sqrt((rwb->scale_step + 1) << 8));
 | 
			
		||||
					int_sqrt((rqd->scale_step + 1) << 8));
 | 
			
		||||
	} else {
 | 
			
		||||
		/*
 | 
			
		||||
		 * For step < 0, we don't want to increase/decrease the
 | 
			
		||||
| 
						 | 
				
			
			@ -433,12 +342,13 @@ static void rwb_arm_timer(struct rq_wb *rwb)
 | 
			
		|||
static void wb_timer_fn(struct blk_stat_callback *cb)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = cb->data;
 | 
			
		||||
	struct rq_depth *rqd = &rwb->rq_depth;
 | 
			
		||||
	unsigned int inflight = wbt_inflight(rwb);
 | 
			
		||||
	int status;
 | 
			
		||||
 | 
			
		||||
	status = latency_exceeded(rwb, cb->stat);
 | 
			
		||||
 | 
			
		||||
	trace_wbt_timer(rwb->queue->backing_dev_info, status, rwb->scale_step,
 | 
			
		||||
	trace_wbt_timer(rwb->rqos.q->backing_dev_info, status, rqd->scale_step,
 | 
			
		||||
			inflight);
 | 
			
		||||
 | 
			
		||||
	/*
 | 
			
		||||
| 
						 | 
				
			
			@ -469,9 +379,9 @@ static void wb_timer_fn(struct blk_stat_callback *cb)
 | 
			
		|||
		 * currently don't have a valid read/write sample. For that
 | 
			
		||||
		 * case, slowly return to center state (step == 0).
 | 
			
		||||
		 */
 | 
			
		||||
		if (rwb->scale_step > 0)
 | 
			
		||||
		if (rqd->scale_step > 0)
 | 
			
		||||
			scale_up(rwb);
 | 
			
		||||
		else if (rwb->scale_step < 0)
 | 
			
		||||
		else if (rqd->scale_step < 0)
 | 
			
		||||
			scale_down(rwb, false);
 | 
			
		||||
		break;
 | 
			
		||||
	default:
 | 
			
		||||
| 
						 | 
				
			
			@ -481,19 +391,50 @@ static void wb_timer_fn(struct blk_stat_callback *cb)
 | 
			
		|||
	/*
 | 
			
		||||
	 * Re-arm timer, if we have IO in flight
 | 
			
		||||
	 */
 | 
			
		||||
	if (rwb->scale_step || inflight)
 | 
			
		||||
	if (rqd->scale_step || inflight)
 | 
			
		||||
		rwb_arm_timer(rwb);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_update_limits(struct rq_wb *rwb)
 | 
			
		||||
static void __wbt_update_limits(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	rwb->scale_step = 0;
 | 
			
		||||
	rwb->scaled_max = false;
 | 
			
		||||
	struct rq_depth *rqd = &rwb->rq_depth;
 | 
			
		||||
 | 
			
		||||
	rqd->scale_step = 0;
 | 
			
		||||
	rqd->scaled_max = false;
 | 
			
		||||
 | 
			
		||||
	rq_depth_calc_max_depth(rqd);
 | 
			
		||||
	calc_wb_limits(rwb);
 | 
			
		||||
 | 
			
		||||
	rwb_wake_all(rwb);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_update_limits(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (!rqos)
 | 
			
		||||
		return;
 | 
			
		||||
	__wbt_update_limits(RQWB(rqos));
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
u64 wbt_get_min_lat(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (!rqos)
 | 
			
		||||
		return 0;
 | 
			
		||||
	return RQWB(rqos)->min_lat_nsec;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_set_min_lat(struct request_queue *q, u64 val)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (!rqos)
 | 
			
		||||
		return;
 | 
			
		||||
	RQWB(rqos)->min_lat_nsec = val;
 | 
			
		||||
	RQWB(rqos)->enable_state = WBT_STATE_ON_MANUAL;
 | 
			
		||||
	__wbt_update_limits(RQWB(rqos));
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
static bool close_io(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	const unsigned long now = jiffies;
 | 
			
		||||
| 
						 | 
				
			
			@ -520,7 +461,7 @@ static inline unsigned int get_limit(struct rq_wb *rwb, unsigned long rw)
 | 
			
		|||
	 * IO for a bit.
 | 
			
		||||
	 */
 | 
			
		||||
	if ((rw & REQ_HIPRIO) || wb_recent_wait(rwb) || current_is_kswapd())
 | 
			
		||||
		limit = rwb->wb_max;
 | 
			
		||||
		limit = rwb->rq_depth.max_depth;
 | 
			
		||||
	else if ((rw & REQ_BACKGROUND) || close_io(rwb)) {
 | 
			
		||||
		/*
 | 
			
		||||
		 * If less than 100ms since we completed unrelated IO,
 | 
			
		||||
| 
						 | 
				
			
			@ -554,7 +495,7 @@ static inline bool may_queue(struct rq_wb *rwb, struct rq_wait *rqw,
 | 
			
		|||
	    rqw->wait.head.next != &wait->entry)
 | 
			
		||||
		return false;
 | 
			
		||||
 | 
			
		||||
	return atomic_inc_below(&rqw->inflight, get_limit(rwb, rw));
 | 
			
		||||
	return rq_wait_inc_below(rqw, get_limit(rwb, rw));
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
| 
						 | 
				
			
			@ -614,8 +555,10 @@ static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)
 | 
			
		|||
 * in an irq held spinlock, if it holds one when calling this function.
 | 
			
		||||
 * If we do sleep, we'll release and re-grab it.
 | 
			
		||||
 */
 | 
			
		||||
enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock)
 | 
			
		||||
static enum wbt_flags wbt_wait(struct rq_qos *rqos, struct bio *bio,
 | 
			
		||||
			       spinlock_t *lock)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
	enum wbt_flags ret = 0;
 | 
			
		||||
 | 
			
		||||
	if (!rwb_enabled(rwb))
 | 
			
		||||
| 
						 | 
				
			
			@ -643,8 +586,10 @@ enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio, spinlock_t *lock)
 | 
			
		|||
	return ret | WBT_TRACKED;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_issue(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
void wbt_issue(struct rq_qos *rqos, struct request *rq)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
 | 
			
		||||
	if (!rwb_enabled(rwb))
 | 
			
		||||
		return;
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -661,8 +606,9 @@ void wbt_issue(struct rq_wb *rwb, struct request *rq)
 | 
			
		|||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_requeue(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
void wbt_requeue(struct rq_qos *rqos, struct request *rq)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
	if (!rwb_enabled(rwb))
 | 
			
		||||
		return;
 | 
			
		||||
	if (rq == rwb->sync_cookie) {
 | 
			
		||||
| 
						 | 
				
			
			@ -671,39 +617,30 @@ void wbt_requeue(struct rq_wb *rwb, struct request *rq)
 | 
			
		|||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
 | 
			
		||||
void wbt_set_queue_depth(struct request_queue *q, unsigned int depth)
 | 
			
		||||
{
 | 
			
		||||
	if (rwb) {
 | 
			
		||||
		rwb->queue_depth = depth;
 | 
			
		||||
		wbt_update_limits(rwb);
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (rqos) {
 | 
			
		||||
		RQWB(rqos)->rq_depth.queue_depth = depth;
 | 
			
		||||
		__wbt_update_limits(RQWB(rqos));
 | 
			
		||||
	}
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_set_write_cache(struct rq_wb *rwb, bool write_cache_on)
 | 
			
		||||
void wbt_set_write_cache(struct request_queue *q, bool write_cache_on)
 | 
			
		||||
{
 | 
			
		||||
	if (rwb)
 | 
			
		||||
		rwb->wc = write_cache_on;
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	if (rqos)
 | 
			
		||||
		RQWB(rqos)->wc = write_cache_on;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Disable wbt, if enabled by default.
 | 
			
		||||
 */
 | 
			
		||||
void wbt_disable_default(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = q->rq_wb;
 | 
			
		||||
 | 
			
		||||
	if (rwb && rwb->enable_state == WBT_STATE_ON_DEFAULT)
 | 
			
		||||
		wbt_exit(q);
 | 
			
		||||
}
 | 
			
		||||
EXPORT_SYMBOL_GPL(wbt_disable_default);
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Enable wbt if defaults are configured that way
 | 
			
		||||
 */
 | 
			
		||||
void wbt_enable_default(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	/* Throttling already enabled? */
 | 
			
		||||
	if (q->rq_wb)
 | 
			
		||||
	if (rqos)
 | 
			
		||||
		return;
 | 
			
		||||
 | 
			
		||||
	/* Queue not registered? Maybe shutting down... */
 | 
			
		||||
| 
						 | 
				
			
			@ -741,6 +678,41 @@ static int wbt_data_dir(const struct request *rq)
 | 
			
		|||
	return -1;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static void wbt_exit(struct rq_qos *rqos)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = RQWB(rqos);
 | 
			
		||||
	struct request_queue *q = rqos->q;
 | 
			
		||||
 | 
			
		||||
	blk_stat_remove_callback(q, rwb->cb);
 | 
			
		||||
	blk_stat_free_callback(rwb->cb);
 | 
			
		||||
	kfree(rwb);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
/*
 | 
			
		||||
 * Disable wbt, if enabled by default.
 | 
			
		||||
 */
 | 
			
		||||
void wbt_disable_default(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_qos *rqos = wbt_rq_qos(q);
 | 
			
		||||
	struct rq_wb *rwb;
 | 
			
		||||
	if (!rqos)
 | 
			
		||||
		return;
 | 
			
		||||
	rwb = RQWB(rqos);
 | 
			
		||||
	if (rwb->enable_state == WBT_STATE_ON_DEFAULT)
 | 
			
		||||
		rwb->wb_normal = 0;
 | 
			
		||||
}
 | 
			
		||||
EXPORT_SYMBOL_GPL(wbt_disable_default);
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
static struct rq_qos_ops wbt_rqos_ops = {
 | 
			
		||||
	.throttle = wbt_wait,
 | 
			
		||||
	.issue = wbt_issue,
 | 
			
		||||
	.requeue = wbt_requeue,
 | 
			
		||||
	.done = wbt_done,
 | 
			
		||||
	.cleanup = __wbt_done,
 | 
			
		||||
	.exit = wbt_exit,
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
int wbt_init(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb;
 | 
			
		||||
| 
						 | 
				
			
			@ -756,39 +728,29 @@ int wbt_init(struct request_queue *q)
 | 
			
		|||
		return -ENOMEM;
 | 
			
		||||
	}
 | 
			
		||||
 | 
			
		||||
	for (i = 0; i < WBT_NUM_RWQ; i++) {
 | 
			
		||||
		atomic_set(&rwb->rq_wait[i].inflight, 0);
 | 
			
		||||
		init_waitqueue_head(&rwb->rq_wait[i].wait);
 | 
			
		||||
	}
 | 
			
		||||
	for (i = 0; i < WBT_NUM_RWQ; i++)
 | 
			
		||||
		rq_wait_init(&rwb->rq_wait[i]);
 | 
			
		||||
 | 
			
		||||
	rwb->rqos.id = RQ_QOS_WBT;
 | 
			
		||||
	rwb->rqos.ops = &wbt_rqos_ops;
 | 
			
		||||
	rwb->rqos.q = q;
 | 
			
		||||
	rwb->last_comp = rwb->last_issue = jiffies;
 | 
			
		||||
	rwb->queue = q;
 | 
			
		||||
	rwb->win_nsec = RWB_WINDOW_NSEC;
 | 
			
		||||
	rwb->enable_state = WBT_STATE_ON_DEFAULT;
 | 
			
		||||
	wbt_update_limits(rwb);
 | 
			
		||||
	rwb->wc = 1;
 | 
			
		||||
	rwb->rq_depth.default_depth = RWB_DEF_DEPTH;
 | 
			
		||||
	__wbt_update_limits(rwb);
 | 
			
		||||
 | 
			
		||||
	/*
 | 
			
		||||
	 * Assign rwb and add the stats callback.
 | 
			
		||||
	 */
 | 
			
		||||
	q->rq_wb = rwb;
 | 
			
		||||
	rq_qos_add(q, &rwb->rqos);
 | 
			
		||||
	blk_stat_add_callback(q, rwb->cb);
 | 
			
		||||
 | 
			
		||||
	rwb->min_lat_nsec = wbt_default_latency_nsec(q);
 | 
			
		||||
 | 
			
		||||
	wbt_set_queue_depth(rwb, blk_queue_depth(q));
 | 
			
		||||
	wbt_set_write_cache(rwb, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 | 
			
		||||
	wbt_set_queue_depth(q, blk_queue_depth(q));
 | 
			
		||||
	wbt_set_write_cache(q, test_bit(QUEUE_FLAG_WC, &q->queue_flags));
 | 
			
		||||
 | 
			
		||||
	return 0;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void wbt_exit(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	struct rq_wb *rwb = q->rq_wb;
 | 
			
		||||
 | 
			
		||||
	if (rwb) {
 | 
			
		||||
		blk_stat_remove_callback(q, rwb->cb);
 | 
			
		||||
		blk_stat_free_callback(rwb->cb);
 | 
			
		||||
		q->rq_wb = NULL;
 | 
			
		||||
		kfree(rwb);
 | 
			
		||||
	}
 | 
			
		||||
}
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
| 
						 | 
				
			
			@ -9,6 +9,7 @@
 | 
			
		|||
#include <linux/ktime.h>
 | 
			
		||||
 | 
			
		||||
#include "blk-stat.h"
 | 
			
		||||
#include "blk-rq-qos.h"
 | 
			
		||||
 | 
			
		||||
enum wbt_flags {
 | 
			
		||||
	WBT_TRACKED		= 1,	/* write, tracked for throttling */
 | 
			
		||||
| 
						 | 
				
			
			@ -35,20 +36,12 @@ enum {
 | 
			
		|||
	WBT_STATE_ON_MANUAL	= 2,
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
struct rq_wait {
 | 
			
		||||
	wait_queue_head_t wait;
 | 
			
		||||
	atomic_t inflight;
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
struct rq_wb {
 | 
			
		||||
	/*
 | 
			
		||||
	 * Settings that govern how we throttle
 | 
			
		||||
	 */
 | 
			
		||||
	unsigned int wb_background;		/* background writeback */
 | 
			
		||||
	unsigned int wb_normal;			/* normal writeback */
 | 
			
		||||
	unsigned int wb_max;			/* max throughput writeback */
 | 
			
		||||
	int scale_step;
 | 
			
		||||
	bool scaled_max;
 | 
			
		||||
 | 
			
		||||
	short enable_state;			/* WBT_STATE_* */
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -67,15 +60,20 @@ struct rq_wb {
 | 
			
		|||
	void *sync_cookie;
 | 
			
		||||
 | 
			
		||||
	unsigned int wc;
 | 
			
		||||
	unsigned int queue_depth;
 | 
			
		||||
 | 
			
		||||
	unsigned long last_issue;		/* last non-throttled issue */
 | 
			
		||||
	unsigned long last_comp;		/* last non-throttled comp */
 | 
			
		||||
	unsigned long min_lat_nsec;
 | 
			
		||||
	struct request_queue *queue;
 | 
			
		||||
	struct rq_qos rqos;
 | 
			
		||||
	struct rq_wait rq_wait[WBT_NUM_RWQ];
 | 
			
		||||
	struct rq_depth rq_depth;
 | 
			
		||||
};
 | 
			
		||||
 | 
			
		||||
static inline struct rq_wb *RQWB(struct rq_qos *rqos)
 | 
			
		||||
{
 | 
			
		||||
	return container_of(rqos, struct rq_wb, rqos);
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
static inline unsigned int wbt_inflight(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
	unsigned int i, ret = 0;
 | 
			
		||||
| 
						 | 
				
			
			@ -86,6 +84,7 @@ static inline unsigned int wbt_inflight(struct rq_wb *rwb)
 | 
			
		|||
	return ret;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
 | 
			
		||||
#ifdef CONFIG_BLK_WBT
 | 
			
		||||
 | 
			
		||||
static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 | 
			
		||||
| 
						 | 
				
			
			@ -93,19 +92,16 @@ static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 | 
			
		|||
	rq->wbt_flags |= flags;
 | 
			
		||||
}
 | 
			
		||||
 | 
			
		||||
void __wbt_done(struct rq_wb *, enum wbt_flags);
 | 
			
		||||
void wbt_done(struct rq_wb *, struct request *);
 | 
			
		||||
enum wbt_flags wbt_wait(struct rq_wb *, struct bio *, spinlock_t *);
 | 
			
		||||
int wbt_init(struct request_queue *);
 | 
			
		||||
void wbt_exit(struct request_queue *);
 | 
			
		||||
void wbt_update_limits(struct rq_wb *);
 | 
			
		||||
void wbt_requeue(struct rq_wb *, struct request *);
 | 
			
		||||
void wbt_issue(struct rq_wb *, struct request *);
 | 
			
		||||
void wbt_update_limits(struct request_queue *);
 | 
			
		||||
void wbt_disable_default(struct request_queue *);
 | 
			
		||||
void wbt_enable_default(struct request_queue *);
 | 
			
		||||
 | 
			
		||||
void wbt_set_queue_depth(struct rq_wb *, unsigned int);
 | 
			
		||||
void wbt_set_write_cache(struct rq_wb *, bool);
 | 
			
		||||
u64 wbt_get_min_lat(struct request_queue *q);
 | 
			
		||||
void wbt_set_min_lat(struct request_queue *q, u64 val);
 | 
			
		||||
 | 
			
		||||
void wbt_set_queue_depth(struct request_queue *, unsigned int);
 | 
			
		||||
void wbt_set_write_cache(struct request_queue *, bool);
 | 
			
		||||
 | 
			
		||||
u64 wbt_default_latency_nsec(struct request_queue *);
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -114,31 +110,11 @@ u64 wbt_default_latency_nsec(struct request_queue *);
 | 
			
		|||
static inline void wbt_track(struct request *rq, enum wbt_flags flags)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void __wbt_done(struct rq_wb *rwb, enum wbt_flags flags)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_done(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline enum wbt_flags wbt_wait(struct rq_wb *rwb, struct bio *bio,
 | 
			
		||||
				      spinlock_t *lock)
 | 
			
		||||
{
 | 
			
		||||
	return 0;
 | 
			
		||||
}
 | 
			
		||||
static inline int wbt_init(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	return -EINVAL;
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_exit(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_update_limits(struct rq_wb *rwb)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_requeue(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_issue(struct rq_wb *rwb, struct request *rq)
 | 
			
		||||
static inline void wbt_update_limits(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_disable_default(struct request_queue *q)
 | 
			
		||||
| 
						 | 
				
			
			@ -147,10 +123,17 @@ static inline void wbt_disable_default(struct request_queue *q)
 | 
			
		|||
static inline void wbt_enable_default(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_set_queue_depth(struct rq_wb *rwb, unsigned int depth)
 | 
			
		||||
static inline void wbt_set_queue_depth(struct request_queue *q, unsigned int depth)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_set_write_cache(struct rq_wb *rwb, bool wc)
 | 
			
		||||
static inline void wbt_set_write_cache(struct request_queue *q, bool wc)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline u64 wbt_get_min_lat(struct request_queue *q)
 | 
			
		||||
{
 | 
			
		||||
	return 0;
 | 
			
		||||
}
 | 
			
		||||
static inline void wbt_set_min_lat(struct request_queue *q, u64 val)
 | 
			
		||||
{
 | 
			
		||||
}
 | 
			
		||||
static inline u64 wbt_default_latency_nsec(struct request_queue *q)
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
| 
						 | 
				
			
			@ -42,7 +42,7 @@ struct bsg_job;
 | 
			
		|||
struct blkcg_gq;
 | 
			
		||||
struct blk_flush_queue;
 | 
			
		||||
struct pr_ops;
 | 
			
		||||
struct rq_wb;
 | 
			
		||||
struct rq_qos;
 | 
			
		||||
struct blk_queue_stats;
 | 
			
		||||
struct blk_stat_callback;
 | 
			
		||||
 | 
			
		||||
| 
						 | 
				
			
			@ -443,7 +443,7 @@ struct request_queue {
 | 
			
		|||
	int			nr_rqs_elvpriv;	/* # allocated rqs w/ elvpriv */
 | 
			
		||||
 | 
			
		||||
	struct blk_queue_stats	*stats;
 | 
			
		||||
	struct rq_wb		*rq_wb;
 | 
			
		||||
	struct rq_qos		*rq_qos;
 | 
			
		||||
 | 
			
		||||
	/*
 | 
			
		||||
	 * If blkcg is not used, @q->root_rl serves all requests.  If blkcg
 | 
			
		||||
| 
						 | 
				
			
			
 | 
			
		|||
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		Reference in a new issue