diff options
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r-- | block/blk-mq.c | 396 |
1 files changed, 256 insertions, 140 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 4e0d173beaa3..0015a1892153 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -41,6 +41,8 @@ #include "blk-mq-sched.h" #include "blk-rq-qos.h" +static DEFINE_PER_CPU(struct list_head, blk_cpu_done); + static void blk_mq_poll_stats_start(struct request_queue *q); static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); @@ -275,26 +277,20 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, { struct blk_mq_tags *tags = blk_mq_tags_from_data(data); struct request *rq = tags->static_rqs[tag]; - req_flags_t rq_flags = 0; - if (data->flags & BLK_MQ_REQ_INTERNAL) { + if (data->q->elevator) { rq->tag = BLK_MQ_NO_TAG; rq->internal_tag = tag; } else { - if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) { - rq_flags = RQF_MQ_INFLIGHT; - atomic_inc(&data->hctx->nr_active); - } rq->tag = tag; rq->internal_tag = BLK_MQ_NO_TAG; - data->hctx->tags->rqs[rq->tag] = rq; } /* csd/requeue_work/fifo_time is initialized before use */ rq->q = data->q; rq->mq_ctx = data->ctx; rq->mq_hctx = data->hctx; - rq->rq_flags = rq_flags; + rq->rq_flags = 0; rq->cmd_flags = data->cmd_flags; if (data->flags & BLK_MQ_REQ_PREEMPT) rq->rq_flags |= RQF_PREEMPT; @@ -362,8 +358,6 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data) data->flags |= BLK_MQ_REQ_NOWAIT; if (e) { - data->flags |= BLK_MQ_REQ_INTERNAL; - /* * Flush requests are special and go directly to the * dispatch list. Don't include reserved tags in the @@ -378,7 +372,7 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data) retry: data->ctx = blk_mq_get_ctx(q); data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx); - if (!(data->flags & BLK_MQ_REQ_INTERNAL)) + if (!e) blk_mq_tag_busy(data->hctx); /* @@ -394,7 +388,7 @@ retry: /* * Give up the CPU and sleep for a random short time to ensure * that thread using a realtime scheduling class are migrated - * off the the CPU, and thus off the hctx that is going away. + * off the CPU, and thus off the hctx that is going away. */ msleep(3); goto retry; @@ -474,9 +468,7 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask); data.ctx = __blk_mq_get_ctx(q, cpu); - if (q->elevator) - data.flags |= BLK_MQ_REQ_INTERNAL; - else + if (!q->elevator) blk_mq_tag_busy(data.hctx); ret = -EWOULDBLOCK; @@ -552,8 +544,7 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error) blk_stat_add(rq, now); } - if (rq->internal_tag != BLK_MQ_NO_TAG) - blk_mq_sched_completed_request(rq, now); + blk_mq_sched_completed_request(rq, now); blk_account_io_done(rq, now); @@ -574,71 +565,139 @@ void blk_mq_end_request(struct request *rq, blk_status_t error) } EXPORT_SYMBOL(blk_mq_end_request); -static void __blk_mq_complete_request_remote(void *data) +/* + * Softirq action handler - move entries to local list and loop over them + * while passing them to the queue registered handler. + */ +static __latent_entropy void blk_done_softirq(struct softirq_action *h) { - struct request *rq = data; - struct request_queue *q = rq->q; + struct list_head *cpu_list, local_list; - q->mq_ops->complete(rq); + local_irq_disable(); + cpu_list = this_cpu_ptr(&blk_cpu_done); + list_replace_init(cpu_list, &local_list); + local_irq_enable(); + + while (!list_empty(&local_list)) { + struct request *rq; + + rq = list_entry(local_list.next, struct request, ipi_list); + list_del_init(&rq->ipi_list); + rq->q->mq_ops->complete(rq); + } } -/** - * blk_mq_force_complete_rq() - Force complete the request, bypassing any error - * injection that could drop the completion. - * @rq: Request to be force completed - * - * Drivers should use blk_mq_complete_request() to complete requests in their - * normal IO path. For timeout error recovery, drivers may call this forced - * completion routine after they've reclaimed timed out requests to bypass - * potentially subsequent fake timeouts. - */ -void blk_mq_force_complete_rq(struct request *rq) +static void blk_mq_trigger_softirq(struct request *rq) { - struct blk_mq_ctx *ctx = rq->mq_ctx; - struct request_queue *q = rq->q; - bool shared = false; - int cpu; + struct list_head *list; + unsigned long flags; + + local_irq_save(flags); + list = this_cpu_ptr(&blk_cpu_done); + list_add_tail(&rq->ipi_list, list); + + /* + * If the list only contains our just added request, signal a raise of + * the softirq. If there are already entries there, someone already + * raised the irq but it hasn't run yet. + */ + if (list->next == &rq->ipi_list) + raise_softirq_irqoff(BLOCK_SOFTIRQ); + local_irq_restore(flags); +} + +static int blk_softirq_cpu_dead(unsigned int cpu) +{ + /* + * If a CPU goes away, splice its entries to the current CPU + * and trigger a run of the softirq + */ + local_irq_disable(); + list_splice_init(&per_cpu(blk_cpu_done, cpu), + this_cpu_ptr(&blk_cpu_done)); + raise_softirq_irqoff(BLOCK_SOFTIRQ); + local_irq_enable(); + + return 0; +} + + +static void __blk_mq_complete_request_remote(void *data) +{ + struct request *rq = data; - WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); /* - * Most of single queue controllers, there is only one irq vector - * for handling IO completion, and the only irq's affinity is set - * as all possible CPUs. On most of ARCHs, this affinity means the - * irq is handled on one specific CPU. + * For most of single queue controllers, there is only one irq vector + * for handling I/O completion, and the only irq's affinity is set + * to all possible CPUs. On most of ARCHs, this affinity means the irq + * is handled on one specific CPU. * - * So complete IO reqeust in softirq context in case of single queue - * for not degrading IO performance by irqsoff latency. + * So complete I/O requests in softirq context in case of single queue + * devices to avoid degrading I/O performance due to irqsoff latency. */ - if (q->nr_hw_queues == 1) { - __blk_complete_request(rq); - return; - } + if (rq->q->nr_hw_queues == 1) + blk_mq_trigger_softirq(rq); + else + rq->q->mq_ops->complete(rq); +} + +static inline bool blk_mq_complete_need_ipi(struct request *rq) +{ + int cpu = raw_smp_processor_id(); + + if (!IS_ENABLED(CONFIG_SMP) || + !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) + return false; + + /* same CPU or cache domain? Complete locally */ + if (cpu == rq->mq_ctx->cpu || + (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) && + cpus_share_cache(cpu, rq->mq_ctx->cpu))) + return false; + + /* don't try to IPI to an offline CPU */ + return cpu_online(rq->mq_ctx->cpu); +} + +bool blk_mq_complete_request_remote(struct request *rq) +{ + WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); /* * For a polled request, always complete locallly, it's pointless * to redirect the completion. */ - if ((rq->cmd_flags & REQ_HIPRI) || - !test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) { - q->mq_ops->complete(rq); - return; - } - - cpu = get_cpu(); - if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) - shared = cpus_share_cache(cpu, ctx->cpu); + if (rq->cmd_flags & REQ_HIPRI) + return false; - if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { + if (blk_mq_complete_need_ipi(rq)) { rq->csd.func = __blk_mq_complete_request_remote; rq->csd.info = rq; rq->csd.flags = 0; - smp_call_function_single_async(ctx->cpu, &rq->csd); + smp_call_function_single_async(rq->mq_ctx->cpu, &rq->csd); } else { - q->mq_ops->complete(rq); + if (rq->q->nr_hw_queues > 1) + return false; + blk_mq_trigger_softirq(rq); } - put_cpu(); + + return true; +} +EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote); + +/** + * blk_mq_complete_request - end I/O on a request + * @rq: the request being processed + * + * Description: + * Complete a request by scheduling the ->complete_rq operation. + **/ +void blk_mq_complete_request(struct request *rq) +{ + if (!blk_mq_complete_request_remote(rq)) + rq->q->mq_ops->complete(rq); } -EXPORT_SYMBOL_GPL(blk_mq_force_complete_rq); +EXPORT_SYMBOL(blk_mq_complete_request); static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) __releases(hctx->srcu) @@ -661,23 +720,6 @@ static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx) } /** - * blk_mq_complete_request - end I/O on a request - * @rq: the request being processed - * - * Description: - * Ends all I/O on a request. It does not handle partial completions. - * The actual completion happens out-of-order, through a IPI handler. - **/ -bool blk_mq_complete_request(struct request *rq) -{ - if (unlikely(blk_should_fake_timeout(rq->q))) - return false; - blk_mq_force_complete_rq(rq); - return true; -} -EXPORT_SYMBOL(blk_mq_complete_request); - -/** * blk_mq_start_request - Start processing a request * @rq: Pointer to request to be started * @@ -1052,6 +1094,45 @@ static inline unsigned int queued_to_index(unsigned int queued) return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); } +static bool __blk_mq_get_driver_tag(struct request *rq) +{ + struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags; + unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags; + int tag; + + blk_mq_tag_busy(rq->mq_hctx); + + if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) { + bt = &rq->mq_hctx->tags->breserved_tags; + tag_offset = 0; + } + + if (!hctx_may_queue(rq->mq_hctx, bt)) + return false; + tag = __sbitmap_queue_get(bt); + if (tag == BLK_MQ_NO_TAG) + return false; + + rq->tag = tag + tag_offset; + return true; +} + +static bool blk_mq_get_driver_tag(struct request *rq) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_driver_tag(rq)) + return false; + + if ((hctx->flags & BLK_MQ_F_TAG_SHARED) && + !(rq->rq_flags & RQF_MQ_INFLIGHT)) { + rq->rq_flags |= RQF_MQ_INFLIGHT; + atomic_inc(&hctx->nr_active); + } + hctx->tags->rqs[rq->tag] = rq; + return true; +} + static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, int flags, void *key) { @@ -1204,25 +1285,70 @@ static void blk_mq_handle_zone_resource(struct request *rq, __blk_mq_requeue_request(rq); } +enum prep_dispatch { + PREP_DISPATCH_OK, + PREP_DISPATCH_NO_TAG, + PREP_DISPATCH_NO_BUDGET, +}; + +static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq, + bool need_budget) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + if (need_budget && !blk_mq_get_dispatch_budget(rq->q)) { + blk_mq_put_driver_tag(rq); + return PREP_DISPATCH_NO_BUDGET; + } + + if (!blk_mq_get_driver_tag(rq)) { + /* + * The initial allocation attempt failed, so we need to + * rerun the hardware queue when a tag is freed. The + * waitqueue takes care of that. If the queue is run + * before we add this entry back on the dispatch list, + * we'll re-run it below. + */ + if (!blk_mq_mark_tag_wait(hctx, rq)) { + /* + * All budgets not got from this function will be put + * together during handling partial dispatch + */ + if (need_budget) + blk_mq_put_dispatch_budget(rq->q); + return PREP_DISPATCH_NO_TAG; + } + } + + return PREP_DISPATCH_OK; +} + +/* release all allocated budgets before calling to blk_mq_dispatch_rq_list */ +static void blk_mq_release_budgets(struct request_queue *q, + unsigned int nr_budgets) +{ + int i; + + for (i = 0; i < nr_budgets; i++) + blk_mq_put_dispatch_budget(q); +} + /* * Returns true if we did some work AND can potentially do more. */ -bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, - bool got_budget) +bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, + unsigned int nr_budgets) { - struct blk_mq_hw_ctx *hctx; + enum prep_dispatch prep; + struct request_queue *q = hctx->queue; struct request *rq, *nxt; - bool no_tag = false; int errors, queued; blk_status_t ret = BLK_STS_OK; - bool no_budget_avail = false; LIST_HEAD(zone_list); if (list_empty(list)) return false; - WARN_ON(!list_is_singular(list) && got_budget); - /* * Now process all the entries, sending them to the driver. */ @@ -1232,32 +1358,10 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, rq = list_first_entry(list, struct request, queuelist); - hctx = rq->mq_hctx; - if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) { - blk_mq_put_driver_tag(rq); - no_budget_avail = true; + WARN_ON_ONCE(hctx != rq->mq_hctx); + prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets); + if (prep != PREP_DISPATCH_OK) break; - } - - if (!blk_mq_get_driver_tag(rq)) { - /* - * The initial allocation attempt failed, so we need to - * rerun the hardware queue when a tag is freed. The - * waitqueue takes care of that. If the queue is run - * before we add this entry back on the dispatch list, - * we'll re-run it below. - */ - if (!blk_mq_mark_tag_wait(hctx, rq)) { - blk_mq_put_dispatch_budget(hctx); - /* - * For non-shared tags, the RESTART check - * will suffice. - */ - if (hctx->flags & BLK_MQ_F_TAG_SHARED) - no_tag = true; - break; - } - } list_del_init(&rq->queuelist); @@ -1274,31 +1378,35 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, bd.last = !blk_mq_get_driver_tag(nxt); } + /* + * once the request is queued to lld, no need to cover the + * budget any more + */ + if (nr_budgets) + nr_budgets--; ret = q->mq_ops->queue_rq(hctx, &bd); - if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { - blk_mq_handle_dev_resource(rq, list); + switch (ret) { + case BLK_STS_OK: + queued++; break; - } else if (ret == BLK_STS_ZONE_RESOURCE) { + case BLK_STS_RESOURCE: + case BLK_STS_DEV_RESOURCE: + blk_mq_handle_dev_resource(rq, list); + goto out; + case BLK_STS_ZONE_RESOURCE: /* * Move the request to zone_list and keep going through * the dispatch list to find more requests the drive can * accept. */ blk_mq_handle_zone_resource(rq, &zone_list); - if (list_empty(list)) - break; - continue; - } - - if (unlikely(ret != BLK_STS_OK)) { + break; + default: errors++; blk_mq_end_request(rq, BLK_STS_IOERR); - continue; } - - queued++; } while (!list_empty(list)); - +out: if (!list_empty(&zone_list)) list_splice_tail_init(&zone_list, list); @@ -1310,6 +1418,12 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, */ if (!list_empty(list)) { bool needs_restart; + /* For non-shared tags, the RESTART check will suffice */ + bool no_tag = prep == PREP_DISPATCH_NO_TAG && + (hctx->flags & BLK_MQ_F_TAG_SHARED); + bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET; + + blk_mq_release_budgets(q, nr_budgets); /* * If we didn't flush the entire list, we could have told @@ -1361,13 +1475,6 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, } else blk_mq_update_dispatch_busy(hctx, false); - /* - * If the host/device is unable to accept more work, inform the - * caller of that. - */ - if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) - return false; - return (queued + errors) != 0; } @@ -1896,11 +2003,11 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (q->elevator && !bypass_insert) goto insert; - if (!blk_mq_get_dispatch_budget(hctx)) + if (!blk_mq_get_dispatch_budget(q)) goto insert; if (!blk_mq_get_driver_tag(rq)) { - blk_mq_put_dispatch_budget(hctx); + blk_mq_put_dispatch_budget(q); goto insert; } @@ -2005,8 +2112,7 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) } /** - * blk_mq_make_request - Create and send a request to block device. - * @q: Request queue pointer. + * blk_mq_submit_bio - Create and send a request to block device. * @bio: Bio pointer. * * Builds up a request structure from @q and @bio and send to the device. The @@ -2020,8 +2126,9 @@ static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) * * Returns: Request queue cookie. */ -blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) +blk_qc_t blk_mq_submit_bio(struct bio *bio) { + struct request_queue *q = bio->bi_disk->queue; const int is_sync = op_is_sync(bio->bi_opf); const int is_flush_fua = op_is_flush(bio->bi_opf); struct blk_mq_alloc_data data = { @@ -2035,7 +2142,7 @@ blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) blk_status_t ret; blk_queue_bounce(q, &bio); - __blk_queue_split(q, &bio, &nr_segs); + __blk_queue_split(&bio, &nr_segs); if (!bio_integrity_prep(bio)) goto queue_exit; @@ -2146,7 +2253,7 @@ queue_exit: blk_queue_exit(q); return BLK_QC_T_NONE; } -EXPORT_SYMBOL_GPL(blk_mq_make_request); /* only for request based dm */ +EXPORT_SYMBOL_GPL(blk_mq_submit_bio); /* only for request based dm */ void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, unsigned int hctx_idx) @@ -2792,7 +2899,7 @@ static void blk_mq_del_queue_tag_set(struct request_queue *q) struct blk_mq_tag_set *set = q->tag_set; mutex_lock(&set->tag_list_lock); - list_del_rcu(&q->tag_set_list); + list_del(&q->tag_set_list); if (list_is_singular(&set->tag_list)) { /* just transitioned to unshared */ set->flags &= ~BLK_MQ_F_TAG_SHARED; @@ -2819,7 +2926,7 @@ static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, } if (set->flags & BLK_MQ_F_TAG_SHARED) queue_set_hctx_shared(q, true); - list_add_tail_rcu(&q->tag_set_list, &set->tag_list); + list_add_tail(&q->tag_set_list, &set->tag_list); mutex_unlock(&set->tag_list_lock); } @@ -2886,7 +2993,7 @@ struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set, { struct request_queue *uninit_q, *q; - uninit_q = __blk_alloc_queue(set->numa_node); + uninit_q = blk_alloc_queue(set->numa_node); if (!uninit_q) return ERR_PTR(-ENOMEM); uninit_q->queuedata = queuedata; @@ -3760,6 +3867,15 @@ EXPORT_SYMBOL(blk_mq_rq_cpu); static int __init blk_mq_init(void) { + int i; + + for_each_possible_cpu(i) + INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i)); + open_softirq(BLOCK_SOFTIRQ, blk_done_softirq); + + cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD, + "block/softirq:dead", NULL, + blk_softirq_cpu_dead); cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, blk_mq_hctx_notify_dead); cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online", |