diff options
Diffstat (limited to 'block/bfq-iosched.c')
| -rw-r--r-- | block/bfq-iosched.c | 445 |
1 files changed, 276 insertions, 169 deletions
diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index 9e81d1052091..b398dde53af9 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -158,7 +158,6 @@ BFQ_BFQQ_FNS(in_large_burst); BFQ_BFQQ_FNS(coop); BFQ_BFQQ_FNS(split_coop); BFQ_BFQQ_FNS(softrt_update); -BFQ_BFQQ_FNS(has_waker); #undef BFQ_BFQQ_FNS \ /* Expiration time of sync (0) and async (1) requests, in ns. */ @@ -1024,9 +1023,16 @@ bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, else bfq_clear_bfqq_IO_bound(bfqq); + bfqq->last_serv_time_ns = bic->saved_last_serv_time_ns; + bfqq->inject_limit = bic->saved_inject_limit; + bfqq->decrease_time_jif = bic->saved_decrease_time_jif; + bfqq->entity.new_weight = bic->saved_weight; bfqq->ttime = bic->saved_ttime; + bfqq->io_start_time = bic->saved_io_start_time; + bfqq->tot_idle_time = bic->saved_tot_idle_time; bfqq->wr_coeff = bic->saved_wr_coeff; + bfqq->service_from_wr = bic->saved_service_from_wr; bfqq->wr_start_at_switch_to_srt = bic->saved_wr_start_at_switch_to_srt; bfqq->last_wr_start_finish = bic->saved_last_wr_start_finish; bfqq->wr_cur_max_time = bic->saved_wr_cur_max_time; @@ -1647,6 +1653,8 @@ static bool bfq_bfqq_higher_class_or_weight(struct bfq_queue *bfqq, return bfqq_weight > in_serv_weight; } +static bool bfq_better_to_idle(struct bfq_queue *bfqq); + static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, struct bfq_queue *bfqq, int old_wr_coeff, @@ -1671,15 +1679,19 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, * - it is sync, * - it does not belong to a large burst, * - it has been idle for enough time or is soft real-time, - * - is linked to a bfq_io_cq (it is not shared in any sense). + * - is linked to a bfq_io_cq (it is not shared in any sense), + * - has a default weight (otherwise we assume the user wanted + * to control its weight explicitly) */ in_burst = bfq_bfqq_in_large_burst(bfqq); soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && !BFQQ_TOTALLY_SEEKY(bfqq) && !in_burst && time_is_before_jiffies(bfqq->soft_rt_next_start) && - bfqq->dispatched == 0; - *interactive = !in_burst && idle_for_long_time; + bfqq->dispatched == 0 && + bfqq->entity.new_weight == 40; + *interactive = !in_burst && idle_for_long_time && + bfqq->entity.new_weight == 40; wr_or_deserves_wr = bfqd->low_latency && (bfqq->wr_coeff > 1 || (bfq_bfqq_sync(bfqq) && @@ -1717,17 +1729,6 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, bfq_clear_bfqq_just_created(bfqq); - - if (!bfq_bfqq_IO_bound(bfqq)) { - if (arrived_in_time) { - bfqq->requests_within_timer++; - if (bfqq->requests_within_timer >= - bfqd->bfq_requests_within_timer) - bfq_mark_bfqq_IO_bound(bfqq); - } else - bfqq->requests_within_timer = 0; - } - if (bfqd->low_latency) { if (unlikely(time_is_after_jiffies(bfqq->split_time))) /* wraparound */ @@ -1755,10 +1756,10 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, bfq_add_bfqq_busy(bfqd, bfqq); /* - * Expire in-service queue only if preemption may be needed - * for guarantees. In particular, we care only about two - * cases. The first is that bfqq has to recover a service - * hole, as explained in the comments on + * Expire in-service queue if preemption may be needed for + * guarantees or throughput. As for guarantees, we care + * explicitly about two cases. The first is that bfqq has to + * recover a service hole, as explained in the comments on * bfq_bfqq_update_budg_for_activation(), i.e., that * bfqq_wants_to_preempt is true. However, if bfqq does not * carry time-critical I/O, then bfqq's bandwidth is less @@ -1785,11 +1786,23 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, * timestamps of the in-service queue would need to be * updated, and this operation is quite costly (see the * comments on bfq_bfqq_update_budg_for_activation()). + * + * As for throughput, we ask bfq_better_to_idle() whether we + * still need to plug I/O dispatching. If bfq_better_to_idle() + * says no, then plugging is not needed any longer, either to + * boost throughput or to perserve service guarantees. Then + * the best option is to stop plugging I/O, as not doing so + * would certainly lower throughput. We may end up in this + * case if: (1) upon a dispatch attempt, we detected that it + * was better to plug I/O dispatch, and to wait for a new + * request to arrive for the currently in-service queue, but + * (2) this switch of bfqq to busy changes the scenario. */ if (bfqd->in_service_queue && ((bfqq_wants_to_preempt && bfqq->wr_coeff >= bfqd->in_service_queue->wr_coeff) || - bfq_bfqq_higher_class_or_weight(bfqq, bfqd->in_service_queue)) && + bfq_bfqq_higher_class_or_weight(bfqq, bfqd->in_service_queue) || + !bfq_better_to_idle(bfqd->in_service_queue)) && next_queue_may_preempt(bfqd)) bfq_bfqq_expire(bfqd, bfqd->in_service_queue, false, BFQQE_PREEMPTED); @@ -1861,6 +1874,138 @@ static void bfq_reset_inject_limit(struct bfq_data *bfqd, bfqq->decrease_time_jif = jiffies; } +static void bfq_update_io_intensity(struct bfq_queue *bfqq, u64 now_ns) +{ + u64 tot_io_time = now_ns - bfqq->io_start_time; + + if (RB_EMPTY_ROOT(&bfqq->sort_list) && bfqq->dispatched == 0) + bfqq->tot_idle_time += + now_ns - bfqq->ttime.last_end_request; + + if (unlikely(bfq_bfqq_just_created(bfqq))) + return; + + /* + * Must be busy for at least about 80% of the time to be + * considered I/O bound. + */ + if (bfqq->tot_idle_time * 5 > tot_io_time) + bfq_clear_bfqq_IO_bound(bfqq); + else + bfq_mark_bfqq_IO_bound(bfqq); + + /* + * Keep an observation window of at most 200 ms in the past + * from now. + */ + if (tot_io_time > 200 * NSEC_PER_MSEC) { + bfqq->io_start_time = now_ns - (tot_io_time>>1); + bfqq->tot_idle_time >>= 1; + } +} + +/* + * Detect whether bfqq's I/O seems synchronized with that of some + * other queue, i.e., whether bfqq, after remaining empty, happens to + * receive new I/O only right after some I/O request of the other + * queue has been completed. We call waker queue the other queue, and + * we assume, for simplicity, that bfqq may have at most one waker + * queue. + * + * A remarkable throughput boost can be reached by unconditionally + * injecting the I/O of the waker queue, every time a new + * bfq_dispatch_request happens to be invoked while I/O is being + * plugged for bfqq. In addition to boosting throughput, this + * unblocks bfqq's I/O, thereby improving bandwidth and latency for + * bfqq. Note that these same results may be achieved with the general + * injection mechanism, but less effectively. For details on this + * aspect, see the comments on the choice of the queue for injection + * in bfq_select_queue(). + * + * Turning back to the detection of a waker queue, a queue Q is deemed + * as a waker queue for bfqq if, for three consecutive times, bfqq + * happens to become non empty right after a request of Q has been + * completed. In particular, on the first time, Q is tentatively set + * as a candidate waker queue, while on the third consecutive time + * that Q is detected, the field waker_bfqq is set to Q, to confirm + * that Q is a waker queue for bfqq. These detection steps are + * performed only if bfqq has a long think time, so as to make it more + * likely that bfqq's I/O is actually being blocked by a + * synchronization. This last filter, plus the above three-times + * requirement, make false positives less likely. + * + * NOTE + * + * The sooner a waker queue is detected, the sooner throughput can be + * boosted by injecting I/O from the waker queue. Fortunately, + * detection is likely to be actually fast, for the following + * reasons. While blocked by synchronization, bfqq has a long think + * time. This implies that bfqq's inject limit is at least equal to 1 + * (see the comments in bfq_update_inject_limit()). So, thanks to + * injection, the waker queue is likely to be served during the very + * first I/O-plugging time interval for bfqq. This triggers the first + * step of the detection mechanism. Thanks again to injection, the + * candidate waker queue is then likely to be confirmed no later than + * during the next I/O-plugging interval for bfqq. + * + * ISSUE + * + * On queue merging all waker information is lost. + */ +static void bfq_check_waker(struct bfq_data *bfqd, struct bfq_queue *bfqq, + u64 now_ns) +{ + if (!bfqd->last_completed_rq_bfqq || + bfqd->last_completed_rq_bfqq == bfqq || + bfq_bfqq_has_short_ttime(bfqq) || + now_ns - bfqd->last_completion >= 4 * NSEC_PER_MSEC || + bfqd->last_completed_rq_bfqq == bfqq->waker_bfqq) + return; + + if (bfqd->last_completed_rq_bfqq != + bfqq->tentative_waker_bfqq) { + /* + * First synchronization detected with a + * candidate waker queue, or with a different + * candidate waker queue from the current one. + */ + bfqq->tentative_waker_bfqq = + bfqd->last_completed_rq_bfqq; + bfqq->num_waker_detections = 1; + } else /* Same tentative waker queue detected again */ + bfqq->num_waker_detections++; + + if (bfqq->num_waker_detections == 3) { + bfqq->waker_bfqq = bfqd->last_completed_rq_bfqq; + bfqq->tentative_waker_bfqq = NULL; + + /* + * If the waker queue disappears, then + * bfqq->waker_bfqq must be reset. To + * this goal, we maintain in each + * waker queue a list, woken_list, of + * all the queues that reference the + * waker queue through their + * waker_bfqq pointer. When the waker + * queue exits, the waker_bfqq pointer + * of all the queues in the woken_list + * is reset. + * + * In addition, if bfqq is already in + * the woken_list of a waker queue, + * then, before being inserted into + * the woken_list of a new waker + * queue, bfqq must be removed from + * the woken_list of the old waker + * queue. + */ + if (!hlist_unhashed(&bfqq->woken_list_node)) + hlist_del_init(&bfqq->woken_list_node); + hlist_add_head(&bfqq->woken_list_node, + &bfqd->last_completed_rq_bfqq->woken_list); + } +} + static void bfq_add_request(struct request *rq) { struct bfq_queue *bfqq = RQ_BFQQ(rq); @@ -1868,117 +2013,14 @@ static void bfq_add_request(struct request *rq) struct request *next_rq, *prev; unsigned int old_wr_coeff = bfqq->wr_coeff; bool interactive = false; + u64 now_ns = ktime_get_ns(); bfq_log_bfqq(bfqd, bfqq, "add_request %d", rq_is_sync(rq)); bfqq->queued[rq_is_sync(rq)]++; bfqd->queued++; if (RB_EMPTY_ROOT(&bfqq->sort_list) && bfq_bfqq_sync(bfqq)) { - /* - * Detect whether bfqq's I/O seems synchronized with - * that of some other queue, i.e., whether bfqq, after - * remaining empty, happens to receive new I/O only - * right after some I/O request of the other queue has - * been completed. We call waker queue the other - * queue, and we assume, for simplicity, that bfqq may - * have at most one waker queue. - * - * A remarkable throughput boost can be reached by - * unconditionally injecting the I/O of the waker - * queue, every time a new bfq_dispatch_request - * happens to be invoked while I/O is being plugged - * for bfqq. In addition to boosting throughput, this - * unblocks bfqq's I/O, thereby improving bandwidth - * and latency for bfqq. Note that these same results - * may be achieved with the general injection - * mechanism, but less effectively. For details on - * this aspect, see the comments on the choice of the - * queue for injection in bfq_select_queue(). - * - * Turning back to the detection of a waker queue, a - * queue Q is deemed as a waker queue for bfqq if, for - * two consecutive times, bfqq happens to become non - * empty right after a request of Q has been - * completed. In particular, on the first time, Q is - * tentatively set as a candidate waker queue, while - * on the second time, the flag - * bfq_bfqq_has_waker(bfqq) is set to confirm that Q - * is a waker queue for bfqq. These detection steps - * are performed only if bfqq has a long think time, - * so as to make it more likely that bfqq's I/O is - * actually being blocked by a synchronization. This - * last filter, plus the above two-times requirement, - * make false positives less likely. - * - * NOTE - * - * The sooner a waker queue is detected, the sooner - * throughput can be boosted by injecting I/O from the - * waker queue. Fortunately, detection is likely to be - * actually fast, for the following reasons. While - * blocked by synchronization, bfqq has a long think - * time. This implies that bfqq's inject limit is at - * least equal to 1 (see the comments in - * bfq_update_inject_limit()). So, thanks to - * injection, the waker queue is likely to be served - * during the very first I/O-plugging time interval - * for bfqq. This triggers the first step of the - * detection mechanism. Thanks again to injection, the - * candidate waker queue is then likely to be - * confirmed no later than during the next - * I/O-plugging interval for bfqq. - */ - if (bfqd->last_completed_rq_bfqq && - !bfq_bfqq_has_short_ttime(bfqq) && - ktime_get_ns() - bfqd->last_completion < - 200 * NSEC_PER_USEC) { - if (bfqd->last_completed_rq_bfqq != bfqq && - bfqd->last_completed_rq_bfqq != - bfqq->waker_bfqq) { - /* - * First synchronization detected with - * a candidate waker queue, or with a - * different candidate waker queue - * from the current one. - */ - bfqq->waker_bfqq = bfqd->last_completed_rq_bfqq; - - /* - * If the waker queue disappears, then - * bfqq->waker_bfqq must be reset. To - * this goal, we maintain in each - * waker queue a list, woken_list, of - * all the queues that reference the - * waker queue through their - * waker_bfqq pointer. When the waker - * queue exits, the waker_bfqq pointer - * of all the queues in the woken_list - * is reset. - * - * In addition, if bfqq is already in - * the woken_list of a waker queue, - * then, before being inserted into - * the woken_list of a new waker - * queue, bfqq must be removed from - * the woken_list of the old waker - * queue. - */ - if (!hlist_unhashed(&bfqq->woken_list_node)) - hlist_del_init(&bfqq->woken_list_node); - hlist_add_head(&bfqq->woken_list_node, - &bfqd->last_completed_rq_bfqq->woken_list); - - bfq_clear_bfqq_has_waker(bfqq); - } else if (bfqd->last_completed_rq_bfqq == - bfqq->waker_bfqq && - !bfq_bfqq_has_waker(bfqq)) { - /* - * synchronization with waker_bfqq - * seen for the second time - */ - bfq_mark_bfqq_has_waker(bfqq); - } - } + bfq_check_waker(bfqd, bfqq, now_ns); /* * Periodically reset inject limit, to make sure that @@ -2047,6 +2089,9 @@ static void bfq_add_request(struct request *rq) } } + if (bfq_bfqq_sync(bfqq)) + bfq_update_io_intensity(bfqq, now_ns); + elv_rb_add(&bfqq->sort_list, rq); /* @@ -2352,6 +2397,24 @@ static void bfq_requests_merged(struct request_queue *q, struct request *rq, /* Must be called with bfqq != NULL */ static void bfq_bfqq_end_wr(struct bfq_queue *bfqq) { + /* + * If bfqq has been enjoying interactive weight-raising, then + * reset soft_rt_next_start. We do it for the following + * reason. bfqq may have been conveying the I/O needed to load + * a soft real-time application. Such an application actually + * exhibits a soft real-time I/O pattern after it finishes + * loading, and finally starts doing its job. But, if bfqq has + * been receiving a lot of bandwidth so far (likely to happen + * on a fast device), then soft_rt_next_start now contains a + * high value that. So, without this reset, bfqq would be + * prevented from being possibly considered as soft_rt for a + * very long time. + */ + + if (bfqq->wr_cur_max_time != + bfqq->bfqd->bfq_wr_rt_max_time) + bfqq->soft_rt_next_start = jiffies; + if (bfq_bfqq_busy(bfqq)) bfqq->bfqd->wr_busy_queues--; bfqq->wr_coeff = 1; @@ -2686,10 +2749,16 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq) if (!bic) return; + bic->saved_last_serv_time_ns = bfqq->last_serv_time_ns; + bic->saved_inject_limit = bfqq->inject_limit; + bic->saved_decrease_time_jif = bfqq->decrease_time_jif; + bic->saved_weight = bfqq->entity.orig_weight; bic->saved_ttime = bfqq->ttime; bic->saved_has_short_ttime = bfq_bfqq_has_short_ttime(bfqq); bic->saved_IO_bound = bfq_bfqq_IO_bound(bfqq); + bic->saved_io_start_time = bfqq->io_start_time; + bic->saved_tot_idle_time = bfqq->tot_idle_time; bic->saved_in_large_burst = bfq_bfqq_in_large_burst(bfqq); bic->was_in_burst_list = !hlist_unhashed(&bfqq->burst_list_node); if (unlikely(bfq_bfqq_just_created(bfqq) && @@ -2712,6 +2781,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq) bic->saved_wr_coeff = bfqq->wr_coeff; bic->saved_wr_start_at_switch_to_srt = bfqq->wr_start_at_switch_to_srt; + bic->saved_service_from_wr = bfqq->service_from_wr; bic->saved_last_wr_start_finish = bfqq->last_wr_start_finish; bic->saved_wr_cur_max_time = bfqq->wr_cur_max_time; } @@ -2937,6 +3007,7 @@ static void __bfq_set_in_service_queue(struct bfq_data *bfqd, } bfqd->in_service_queue = bfqq; + bfqd->in_serv_last_pos = 0; } /* @@ -3442,20 +3513,38 @@ static void bfq_dispatch_remove(struct request_queue *q, struct request *rq) * order until all the requests already queued in the device have been * served. The last sub-condition commented above somewhat mitigates * this problem for weight-raised queues. + * + * However, as an additional mitigation for this problem, we preserve + * plugging for a special symmetric case that may suddenly turn into + * asymmetric: the case where only bfqq is busy. In this case, not + * expiring bfqq does not cause any harm to any other queues in terms + * of service guarantees. In contrast, it avoids the following unlucky + * sequence of events: (1) bfqq is expired, (2) a new queue with a + * lower weight than bfqq becomes busy (or more queues), (3) the new + * queue is served until a new request arrives for bfqq, (4) when bfqq + * is finally served, there are so many requests of the new queue in + * the drive that the pending requests for bfqq take a lot of time to + * be served. In particular, event (2) may case even already + * dispatched requests of bfqq to be delayed, inside the drive. So, to + * avoid this series of events, the scenario is preventively declared + * as asymmetric also if bfqq is the only busy queues */ static bool idling_needed_for_service_guarantees(struct bfq_data *bfqd, struct bfq_queue *bfqq) { + int tot_busy_queues = bfq_tot_busy_queues(bfqd); + /* No point in idling for bfqq if it won't get requests any longer */ if (unlikely(!bfqq_process_refs(bfqq))) return false; return (bfqq->wr_coeff > 1 && (bfqd->wr_busy_queues < - bfq_tot_busy_queues(bfqd) || + tot_busy_queues || bfqd->rq_in_driver >= bfqq->dispatched + 4)) || - bfq_asymmetric_scenario(bfqd, bfqq); + bfq_asymmetric_scenario(bfqd, bfqq) || + tot_busy_queues == 1; } static bool __bfq_bfqq_expire(struct bfq_data *bfqd, struct bfq_queue *bfqq, @@ -3939,10 +4028,6 @@ void bfq_bfqq_expire(struct bfq_data *bfqd, bfq_bfqq_budget_left(bfqq) >= entity->budget / 3))) bfq_bfqq_charge_time(bfqd, bfqq, delta); - if (reason == BFQQE_TOO_IDLE && - entity->service <= 2 * entity->budget / 10) - bfq_clear_bfqq_IO_bound(bfqq); - if (bfqd->low_latency && bfqq->wr_coeff == 1) bfqq->last_wr_start_finish = jiffies; @@ -3952,30 +4037,15 @@ void bfq_bfqq_expire(struct bfq_data *bfqd, * If we get here, and there are no outstanding * requests, then the request pattern is isochronous * (see the comments on the function - * bfq_bfqq_softrt_next_start()). Thus we can compute - * soft_rt_next_start. And we do it, unless bfqq is in - * interactive weight raising. We do not do it in the - * latter subcase, for the following reason. bfqq may - * be conveying the I/O needed to load a soft - * real-time application. Such an application will - * actually exhibit a soft real-time I/O pattern after - * it finally starts doing its job. But, if - * soft_rt_next_start is computed here for an - * interactive bfqq, and bfqq had received a lot of - * service before remaining with no outstanding - * request (likely to happen on a fast device), then - * soft_rt_next_start would be assigned such a high - * value that, for a very long time, bfqq would be - * prevented from being possibly considered as soft - * real time. + * bfq_bfqq_softrt_next_start()). Therefore we can + * compute soft_rt_next_start. * * If, instead, the queue still has outstanding * requests, then we have to wait for the completion * of all the outstanding requests to discover whether * the request pattern is actually isochronous. */ - if (bfqq->dispatched == 0 && - bfqq->wr_coeff != bfqd->bfq_wr_coeff) + if (bfqq->dispatched == 0) bfqq->soft_rt_next_start = bfq_bfqq_softrt_next_start(bfqd, bfqq); else if (bfqq->dispatched > 0) { @@ -4497,9 +4567,9 @@ check_queue: bfq_serv_to_charge(async_bfqq->next_rq, async_bfqq) <= bfq_bfqq_budget_left(async_bfqq)) bfqq = bfqq->bic->bfqq[0]; - else if (bfq_bfqq_has_waker(bfqq) && + else if (bfqq->waker_bfqq && bfq_bfqq_busy(bfqq->waker_bfqq) && - bfqq->next_rq && + bfqq->waker_bfqq->next_rq && bfq_serv_to_charge(bfqq->waker_bfqq->next_rq, bfqq->waker_bfqq) <= bfq_bfqq_budget_left(bfqq->waker_bfqq) @@ -4559,9 +4629,21 @@ static void bfq_update_wr_data(struct bfq_data *bfqd, struct bfq_queue *bfqq) bfqq->wr_cur_max_time)) { if (bfqq->wr_cur_max_time != bfqd->bfq_wr_rt_max_time || time_is_before_jiffies(bfqq->wr_start_at_switch_to_srt + - bfq_wr_duration(bfqd))) + bfq_wr_duration(bfqd))) { + /* + * Either in interactive weight + * raising, or in soft_rt weight + * raising with the + * interactive-weight-raising period + * elapsed (so no switch back to + * interactive weight raising). + */ bfq_bfqq_end_wr(bfqq); - else { + } else { /* + * soft_rt finishing while still in + * interactive period, switch back to + * interactive weight raising + */ switch_back_to_interactive_wr(bfqq, bfqd); bfqq->entity.prio_changed = 1; } @@ -4640,9 +4722,6 @@ static bool bfq_has_work(struct blk_mq_hw_ctx *hctx) { struct bfq_data *bfqd = hctx->queue->elevator->elevator_data; - if (!atomic_read(&hctx->elevator_queued)) - return false; - /* * Avoiding lock: a race on bfqd->busy_queues should cause at * most a call to dispatch for nothing @@ -4892,7 +4971,6 @@ void bfq_put_queue(struct bfq_queue *bfqq) hlist_for_each_entry_safe(item, n, &bfqq->woken_list, woken_list_node) { item->waker_bfqq = NULL; - bfq_clear_bfqq_has_waker(item); hlist_del_init(&item->woken_list_node); } @@ -5012,6 +5090,8 @@ bfq_set_next_ioprio_data(struct bfq_queue *bfqq, struct bfq_io_cq *bic) } bfqq->entity.new_weight = bfq_ioprio_to_weight(bfqq->new_ioprio); + bfq_log_bfqq(bfqd, bfqq, "new_ioprio %d new_weight %d", + bfqq->new_ioprio, bfqq->entity.new_weight); bfqq->entity.prio_changed = 1; } @@ -5049,6 +5129,8 @@ static void bfq_check_ioprio_change(struct bfq_io_cq *bic, struct bio *bio) static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, struct bfq_io_cq *bic, pid_t pid, int is_sync) { + u64 now_ns = ktime_get_ns(); + RB_CLEAR_NODE(&bfqq->entity.rb_node); INIT_LIST_HEAD(&bfqq->fifo); INIT_HLIST_NODE(&bfqq->burst_list_node); @@ -5076,7 +5158,9 @@ static void bfq_init_bfqq(struct bfq_data *bfqd, struct bfq_queue *bfqq, bfq_clear_bfqq_sync(bfqq); /* set end request to minus infinity from now */ - bfqq->ttime.last_end_request = ktime_get_ns() + 1; + bfqq->ttime.last_end_request = now_ns + 1; + + bfqq->io_start_time = now_ns; bfq_mark_bfqq_IO_bound(bfqq); @@ -5194,11 +5278,19 @@ static void bfq_update_io_thinktime(struct bfq_data *bfqd, struct bfq_queue *bfqq) { struct bfq_ttime *ttime = &bfqq->ttime; - u64 elapsed = ktime_get_ns() - bfqq->ttime.last_end_request; + u64 elapsed; + /* + * We are really interested in how long it takes for the queue to + * become busy when there is no outstanding IO for this queue. So + * ignore cases when the bfq queue has already IO queued. + */ + if (bfqq->dispatched || bfq_bfqq_busy(bfqq)) + return; + elapsed = ktime_get_ns() - bfqq->ttime.last_end_request; elapsed = min_t(u64, elapsed, 2ULL * bfqd->bfq_slice_idle); - ttime->ttime_samples = (7*bfqq->ttime.ttime_samples + 256) / 8; + ttime->ttime_samples = (7*ttime->ttime_samples + 256) / 8; ttime->ttime_total = div_u64(7*ttime->ttime_total + 256*elapsed, 8); ttime->ttime_mean = div64_ul(ttime->ttime_total + 128, ttime->ttime_samples); @@ -5213,8 +5305,26 @@ bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, if (bfqq->wr_coeff > 1 && bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && - BFQQ_TOTALLY_SEEKY(bfqq)) - bfq_bfqq_end_wr(bfqq); + BFQQ_TOTALLY_SEEKY(bfqq)) { + if (time_is_before_jiffies(bfqq->wr_start_at_switch_to_srt + + bfq_wr_duration(bfqd))) { + /* + * In soft_rt weight raising with the + * interactive-weight-raising period + * elapsed (so no switch back to + * interactive weight raising). + */ + bfq_bfqq_end_wr(bfqq); + } else { /* + * stopping soft_rt weight raising + * while still in interactive period, + * switch back to interactive weight + * raising + */ + switch_back_to_interactive_wr(bfqq, bfqd); + bfqq->entity.prio_changed = 1; + } + } } static void bfq_update_has_short_ttime(struct bfq_data *bfqd, @@ -5238,12 +5348,13 @@ static void bfq_update_has_short_ttime(struct bfq_data *bfqd, return; /* Think time is infinite if no process is linked to - * bfqq. Otherwise check average think time to - * decide whether to mark as has_short_ttime + * bfqq. Otherwise check average think time to decide whether + * to mark as has_short_ttime. To this goal, compare average + * think time with half the I/O-plugging timeout. */ if (atomic_read(&bic->icq.ioc->active_ref) == 0 || (bfq_sample_valid(bfqq->ttime.ttime_samples) && - bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle)) + bfqq->ttime.ttime_mean > bfqd->bfq_slice_idle>>1)) has_short_ttime = false; state_changed = has_short_ttime != bfq_bfqq_has_short_ttime(bfqq); @@ -5557,7 +5668,6 @@ static void bfq_insert_requests(struct blk_mq_hw_ctx *hctx, rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); bfq_insert_request(hctx, rq, at_head); - atomic_inc(&hctx->elevator_queued); } } @@ -5925,7 +6035,6 @@ static void bfq_finish_requeue_request(struct request *rq) bfq_completed_request(bfqq, bfqd); bfq_finish_requeue_request_body(bfqq); - atomic_dec(&rq->mq_hctx->elevator_queued); spin_unlock_irqrestore(&bfqd->lock, flags); } else { @@ -6489,8 +6598,6 @@ static int bfq_init_queue(struct request_queue *q, struct elevator_type *e) bfqd->bfq_slice_idle = bfq_slice_idle; bfqd->bfq_timeout = bfq_timeout; - bfqd->bfq_requests_within_timer = 120; - bfqd->bfq_large_burst_thresh = 8; bfqd->bfq_burst_interval = msecs_to_jiffies(180); |