2018-07-03 22:32:35 +07:00
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#include "blk-rq-qos.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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2018-07-20 08:42:13 +07:00
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static bool atomic_inc_below(atomic_t *v, unsigned int below)
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2018-07-03 22:32:35 +07:00
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{
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2018-07-20 08:42:13 +07:00
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unsigned int cur = atomic_read(v);
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2018-07-03 22:32:35 +07:00
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for (;;) {
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2018-07-20 08:42:13 +07:00
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unsigned int old;
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2018-07-03 22:32:35 +07:00
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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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2018-07-20 08:42:13 +07:00
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bool rq_wait_inc_below(struct rq_wait *rq_wait, unsigned int limit)
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2018-07-03 22:32:35 +07:00
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{
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return atomic_inc_below(&rq_wait->inflight, limit);
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}
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2018-07-03 22:14:59 +07:00
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void rq_qos_cleanup(struct request_queue *q, struct bio *bio)
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2018-07-03 22:32:35 +07:00
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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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2018-07-03 22:14:59 +07:00
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rqos->ops->cleanup(rqos, bio);
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2018-07-03 22:32:35 +07:00
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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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2018-07-03 22:14:59 +07:00
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void rq_qos_throttle(struct request_queue *q, struct bio *bio,
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spinlock_t *lock)
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2018-07-03 22:32:35 +07:00
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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->throttle)
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2018-07-03 22:14:59 +07:00
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rqos->ops->throttle(rqos, bio, lock);
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}
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}
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void rq_qos_track(struct request_queue *q, struct request *rq, struct bio *bio)
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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->track)
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rqos->ops->track(rqos, rq, bio);
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2018-07-03 22:32:35 +07:00
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}
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}
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2018-07-03 22:15:00 +07:00
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void rq_qos_done_bio(struct request_queue *q, struct bio *bio)
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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_bio)
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rqos->ops->done_bio(rqos, bio);
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}
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}
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2018-07-03 22:32:35 +07:00
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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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