blk-wbt.c (d62118b6dd99b8f64350206a6ea6996083b28c9a) blk-wbt.c (a6f0788ec2881ac14e97ff7fa6a78a807f87b5ba)
1/*
2 * buffered writeback throttling. loosely based on CoDel. We can't drop
3 * packets for IO scheduling, so the logic is something like this:
4 *
5 * - Monitor latencies in a defined window of time.
6 * - If the minimum latency in the above window exceeds some target, increment
7 * scaling step and scale down queue depth by a factor of 2x. The monitoring
8 * window is then shrunk to 100 / sqrt(scaling step + 1).

--- 561 unchanged lines hidden (view full) ---

570 finish_wait(&rqw->wait, &wait);
571}
572
573static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)
574{
575 const int op = bio_op(bio);
576
577 /*
1/*
2 * buffered writeback throttling. loosely based on CoDel. We can't drop
3 * packets for IO scheduling, so the logic is something like this:
4 *
5 * - Monitor latencies in a defined window of time.
6 * - If the minimum latency in the above window exceeds some target, increment
7 * scaling step and scale down queue depth by a factor of 2x. The monitoring
8 * window is then shrunk to 100 / sqrt(scaling step + 1).

--- 561 unchanged lines hidden (view full) ---

570 finish_wait(&rqw->wait, &wait);
571}
572
573static inline bool wbt_should_throttle(struct rq_wb *rwb, struct bio *bio)
574{
575 const int op = bio_op(bio);
576
577 /*
578 * If not a WRITE (or a discard), do nothing
578 * If not a WRITE (or a discard or write zeroes), do nothing
579 */
579 */
580 if (!(op == REQ_OP_WRITE || op == REQ_OP_DISCARD))
580 if (!(op == REQ_OP_WRITE || op == REQ_OP_DISCARD ||
581 op == REQ_OP_WRITE_ZEROES))
581 return false;
582
583 /*
584 * Don't throttle WRITE_ODIRECT
585 */
586 if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE))
587 return false;
588

--- 162 unchanged lines hidden --- 		582 return false;
583
584 /*
585 * Don't throttle WRITE_ODIRECT
586 */
587 if ((bio->bi_opf & (REQ_SYNC | REQ_IDLE)) == (REQ_SYNC | REQ_IDLE))
588 return false;
589

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