From fd571df0ac5b289af8c659891f9b72f4c0cfdbd2 Mon Sep 17 00:00:00 2001 From: Paolo Valente Date: Tue, 3 Jan 2023 15:54:59 +0100 Subject: [PATCH] block, bfq: turn bfqq_data into an array in bfq_io_cq When a bfq_queue Q is merged with another queue, several pieces of information are saved about Q. These pieces are stored in the bfqq_data field in the bfq_io_cq data structure of the process associated with Q. Yet, with a multi-actuator drive, a process may get associated with multiple bfq_queues: one queue for each of the N actuators. Each of these queues may undergo a merge. So, the bfq_io_cq data structure must be able to accommodate the above information for N queues. This commit solves this problem by turning the bfqq_data scalar field into an array of N elements (and by changing code so as to handle this array). This solution is written under the assumption that bfq_queues associated with different actuators cannot be cross-merged. This assumption holds naturally with basic queue merging: the latter is triggered by spatial locality, and sectors for different actuators are not close to each other (apart from the corner case of the last sectors served by a given actuator and the first sectors served by the next actuator). As for stable cross-merging, the assumption here is that it is disabled. Reviewed-by: Damien Le Moal Signed-off-by: Gabriele Felici Signed-off-by: Gianmarco Lusvardi Signed-off-by: Giulio Barabino Signed-off-by: Emiliano Maccaferri Signed-off-by: Paolo Valente Link: https://lore.kernel.org/r/20230103145503.71712-5-paolo.valente@linaro.org Signed-off-by: Jens Axboe --- block/bfq-iosched.c | 100 +++++++++++++++++++++++++++++++--------------------- block/bfq-iosched.h | 12 ++++--- 2 files changed, 67 insertions(+), 45 deletions(-) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index cefd16b9cbd1..9675a32af0f4 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -408,7 +408,7 @@ void bic_set_bfqq(struct bfq_io_cq *bic, * we cancel the stable merge if * bic->stable_merge_bfqq == bfqq. */ - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; + struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data[actuator_idx]; /* Clear bic pointer if bfqq is detached from this bic */ if (old_bfqq && old_bfqq->bic == bic) @@ -1135,9 +1135,10 @@ static void bfq_bfqq_resume_state(struct bfq_queue *bfqq, struct bfq_data *bfqd, struct bfq_io_cq *bic, bool bfq_already_existing) { - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; unsigned int old_wr_coeff = 1; bool busy = bfq_already_existing && bfq_bfqq_busy(bfqq); + unsigned int a_idx = bfqq->actuator_idx; + struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data[a_idx]; if (bfqq_data->saved_has_short_ttime) bfq_mark_bfqq_has_short_ttime(bfqq); @@ -1818,7 +1819,9 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, arrived_in_time = ktime_get_ns() <= bfqq->ttime.last_end_request + bfqd->bfq_slice_idle * 3; - + unsigned int act_idx = bfq_actuator_index(bfqd, rq->bio); + bool bfqq_non_merged_or_stably_merged = + bfqq->bic || RQ_BIC(rq)->bfqq_data[act_idx].stably_merged; /* * bfqq deserves to be weight-raised if: @@ -1852,9 +1855,8 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, */ wr_or_deserves_wr = bfqd->low_latency && (bfqq->wr_coeff > 1 || - (bfq_bfqq_sync(bfqq) && - (bfqq->bic || RQ_BIC(rq)->bfqq_data.stably_merged) && - (*interactive || soft_rt))); + (bfq_bfqq_sync(bfqq) && bfqq_non_merged_or_stably_merged && + (*interactive || soft_rt))); /* * Using the last flag, update budget and check whether bfqq @@ -2828,6 +2830,35 @@ static bool bfq_may_be_close_cooperator(struct bfq_queue *bfqq, static bool idling_boosts_thr_without_issues(struct bfq_data *bfqd, struct bfq_queue *bfqq); +static struct bfq_queue * +bfq_setup_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq, + struct bfq_queue *stable_merge_bfqq, + struct bfq_iocq_bfqq_data *bfqq_data) +{ + int proc_ref = min(bfqq_process_refs(bfqq), + bfqq_process_refs(stable_merge_bfqq)); + struct bfq_queue *new_bfqq; + + if (idling_boosts_thr_without_issues(bfqd, bfqq) || + proc_ref == 0) + return NULL; + + /* next function will take at least one ref */ + new_bfqq = bfq_setup_merge(bfqq, stable_merge_bfqq); + + if (new_bfqq) { + bfqq_data->stably_merged = true; + if (new_bfqq->bic) { + unsigned int new_a_idx = new_bfqq->actuator_idx; + struct bfq_iocq_bfqq_data *new_bfqq_data = + &new_bfqq->bic->bfqq_data[new_a_idx]; + + new_bfqq_data->stably_merged = true; + } + } + return new_bfqq; +} + /* * Attempt to schedule a merge of bfqq with the currently in-service * queue or with a close queue among the scheduled queues. Return @@ -2853,7 +2884,8 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, void *io_struct, bool request, struct bfq_io_cq *bic) { struct bfq_queue *in_service_bfqq, *new_bfqq; - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; + unsigned int a_idx = bfqq->actuator_idx; + struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data[a_idx]; /* if a merge has already been setup, then proceed with that first */ if (bfqq->new_bfqq) @@ -2883,29 +2915,15 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, msecs_to_jiffies(bfq_late_stable_merging))) { struct bfq_queue *stable_merge_bfqq = bfqq_data->stable_merge_bfqq; - int proc_ref = min(bfqq_process_refs(bfqq), - bfqq_process_refs(stable_merge_bfqq)); /* deschedule stable merge, because done or aborted here */ bfq_put_stable_ref(stable_merge_bfqq); bfqq_data->stable_merge_bfqq = NULL; - if (!idling_boosts_thr_without_issues(bfqd, bfqq) && - proc_ref > 0) { - /* next function will take at least one ref */ - struct bfq_queue *new_bfqq = - bfq_setup_merge(bfqq, stable_merge_bfqq); - - if (new_bfqq) { - bfqq_data->stably_merged = true; - if (new_bfqq->bic) - new_bfqq->bic->bfqq_data.stably_merged = - true; - } - return new_bfqq; - } else - return NULL; + return bfq_setup_stable_merge(bfqd, bfqq, + stable_merge_bfqq, + bfqq_data); } } @@ -3000,7 +3018,8 @@ bfq_setup_cooperator(struct bfq_data *bfqd, struct bfq_queue *bfqq, static void bfq_bfqq_save_state(struct bfq_queue *bfqq) { struct bfq_io_cq *bic = bfqq->bic; - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; + unsigned int a_idx = bfqq->actuator_idx; + struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data[a_idx]; /* * If !bfqq->bic, the queue is already shared or its requests @@ -3011,7 +3030,7 @@ static void bfq_bfqq_save_state(struct bfq_queue *bfqq) return; bfqq_data->saved_last_serv_time_ns = bfqq->last_serv_time_ns; - bfqq_data->saved_inject_limit = bfqq->inject_limit; + bfqq_data->saved_inject_limit = bfqq->inject_limit; bfqq_data->saved_decrease_time_jif = bfqq->decrease_time_jif; bfqq_data->saved_weight = bfqq->entity.orig_weight; @@ -5377,7 +5396,7 @@ static void bfq_exit_icq(struct io_cq *icq) * therefore on its unused per-actuator fields being NULL. */ unsigned int num_actuators = BFQ_MAX_ACTUATORS; - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; + struct bfq_iocq_bfqq_data *bfqq_data = bic->bfqq_data; /* * bfqd is NULL if scheduler already exited, and in that case @@ -5388,10 +5407,10 @@ static void bfq_exit_icq(struct io_cq *icq) num_actuators = bfqd->num_actuators; } - if (bfqq_data->stable_merge_bfqq) - bfq_put_stable_ref(bfqq_data->stable_merge_bfqq); - for (act_idx = 0; act_idx < num_actuators; act_idx++) { + if (bfqq_data[act_idx].stable_merge_bfqq) + bfq_put_stable_ref(bfqq_data[act_idx].stable_merge_bfqq); + bfq_exit_icq_bfqq(bic, true, act_idx); bfq_exit_icq_bfqq(bic, false, act_idx); } @@ -5578,16 +5597,16 @@ bfq_do_early_stable_merge(struct bfq_data *bfqd, struct bfq_queue *bfqq, struct bfq_io_cq *bic, struct bfq_queue *last_bfqq_created) { + unsigned int a_idx = last_bfqq_created->actuator_idx; struct bfq_queue *new_bfqq = bfq_setup_merge(bfqq, last_bfqq_created); - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; if (!new_bfqq) return bfqq; if (new_bfqq->bic) - new_bfqq->bic->bfqq_data.stably_merged = true; - bfqq_data->stably_merged = true; + new_bfqq->bic->bfqq_data[a_idx].stably_merged = true; + bic->bfqq_data[a_idx].stably_merged = true; /* * Reusing merge functions. This implies that @@ -5656,7 +5675,6 @@ static struct bfq_queue *bfq_do_or_sched_stable_merge(struct bfq_data *bfqd, &bfqd->last_bfqq_created; struct bfq_queue *last_bfqq_created = *source_bfqq; - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; /* * If last_bfqq_created has not been set yet, then init it. If @@ -5718,7 +5736,8 @@ static struct bfq_queue *bfq_do_or_sched_stable_merge(struct bfq_data *bfqd, /* * Record the bfqq to merge to. */ - bfqq_data->stable_merge_bfqq = last_bfqq_created; + bic->bfqq_data[last_bfqq_created->actuator_idx].stable_merge_bfqq = + last_bfqq_created; } } @@ -6639,7 +6658,7 @@ static struct bfq_queue *bfq_get_bfqq_handle_split(struct bfq_data *bfqd, { unsigned int act_idx = bfq_actuator_index(bfqd, bio); struct bfq_queue *bfqq = bic_to_bfqq(bic, is_sync, act_idx); - struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data; + struct bfq_iocq_bfqq_data *bfqq_data = &bic->bfqq_data[act_idx]; if (likely(bfqq && bfqq != &bfqd->oom_bfqq)) return bfqq; @@ -6747,7 +6766,7 @@ static struct bfq_queue *bfq_init_rq(struct request *rq) struct bfq_queue *bfqq; bool new_queue = false; bool bfqq_already_existing = false, split = false; - struct bfq_iocq_bfqq_data *bfqq_data; + unsigned int a_idx = bfq_actuator_index(bfqd, bio); if (unlikely(!rq->elv.icq)) return NULL; @@ -6771,17 +6790,16 @@ static struct bfq_queue *bfq_init_rq(struct request *rq) bfqq = bfq_get_bfqq_handle_split(bfqd, bic, bio, false, is_sync, &new_queue); - bfqq_data = &bic->bfqq_data; - if (likely(!new_queue)) { /* If the queue was seeky for too long, break it apart. */ if (bfq_bfqq_coop(bfqq) && bfq_bfqq_split_coop(bfqq) && - !bfqq_data->stably_merged) { + !bic->bfqq_data[a_idx].stably_merged) { struct bfq_queue *old_bfqq = bfqq; /* Update bic before losing reference to bfqq */ if (bfq_bfqq_in_large_burst(bfqq)) - bfqq_data->saved_in_large_burst = true; + bic->bfqq_data[a_idx].saved_in_large_burst = + true; bfqq = bfq_split_bfqq(bic, bfqq); split = true; diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h index 33d43d6bd6c2..28a884b13736 100644 --- a/block/bfq-iosched.h +++ b/block/bfq-iosched.h @@ -418,7 +418,7 @@ struct bfq_queue { struct bfq_iocq_bfqq_data { /* * Snapshot of the has_short_time flag before merging; taken - * to remember its value while the queue is merged, so as to + * to remember its values while the queue is merged, so as to * be able to restore it in case of split. */ bool saved_has_short_ttime; @@ -432,7 +432,7 @@ struct bfq_iocq_bfqq_data { u64 saved_tot_idle_time; /* - * Same purpose as the previous fields for the value of the + * Same purpose as the previous fields for the values of the * field keeping the queue's belonging to a large burst */ bool saved_in_large_burst; @@ -495,8 +495,12 @@ struct bfq_io_cq { uint64_t blkcg_serial_nr; /* the current blkcg serial */ #endif - /* persistent data for associated synchronous process queue */ - struct bfq_iocq_bfqq_data bfqq_data; + /* + * Persistent data for associated synchronous process queues + * (one queue per actuator, see field bfqq above). In + * particular, each of these queues may undergo a merge. + */ + struct bfq_iocq_bfqq_data bfqq_data[BFQ_MAX_ACTUATORS]; unsigned int requests; /* Number of requests this process has in flight */ }; -- 2.11.0