diff options
| -rw-r--r-- | block/blk-mq-sched.c | 55 | ||||
| -rw-r--r-- | block/blk-mq-sched.h | 2 | ||||
| -rw-r--r-- | block/blk-mq.c | 43 | ||||
| -rw-r--r-- | block/blk-mq.h | 20 | ||||
| -rw-r--r-- | include/linux/blk-mq.h | 11 |
5 files changed, 114 insertions, 17 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index be29ba8..8e525e6 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -89,31 +89,57 @@ static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx) return false; } -static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) +/* return true if hctx need to run again */ +static bool blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; LIST_HEAD(rq_list); do { - struct request *rq = e->type->ops.mq.dispatch_request(hctx); + struct request *rq; + blk_status_t ret; - if (!rq) + if (e->type->ops.mq.has_work && + !e->type->ops.mq.has_work(hctx)) break; + + ret = blk_mq_get_dispatch_budget(hctx); + if (ret == BLK_STS_RESOURCE) + return true; + + rq = e->type->ops.mq.dispatch_request(hctx); + if (!rq) { + blk_mq_put_dispatch_budget(hctx); + break; + } else if (ret != BLK_STS_OK) { + blk_mq_end_request(rq, ret); + continue; + } + + /* + * Now this rq owns the budget which has to be released + * if this rq won't be queued to driver via .queue_rq() + * in blk_mq_dispatch_rq_list(). + */ list_add(&rq->queuelist, &rq_list); - } while (blk_mq_dispatch_rq_list(q, &rq_list)); + } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); + + return false; } -void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) +/* return true if hw queue need to be run again */ +bool blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; LIST_HEAD(rq_list); + bool run_queue = false; /* RCU or SRCU read lock is needed before checking quiesced flag */ if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) - return; + return false; hctx->run++; @@ -143,14 +169,23 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) */ if (!list_empty(&rq_list)) { blk_mq_sched_mark_restart_hctx(hctx); - if (blk_mq_dispatch_rq_list(q, &rq_list) && has_sched_dispatch) - blk_mq_do_dispatch_sched(hctx); + if (blk_mq_dispatch_rq_list(q, &rq_list, false) && + has_sched_dispatch) + run_queue = blk_mq_do_dispatch_sched(hctx); } else if (has_sched_dispatch) { - blk_mq_do_dispatch_sched(hctx); + run_queue = blk_mq_do_dispatch_sched(hctx); } else { blk_mq_flush_busy_ctxs(hctx, &rq_list); - blk_mq_dispatch_rq_list(q, &rq_list); + blk_mq_dispatch_rq_list(q, &rq_list, false); } + + if (run_queue && !blk_mq_sched_needs_restart(hctx) && + !test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state)) { + blk_mq_sched_mark_restart_hctx(hctx); + return true; + } + + return false; } bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index 9267d0b7..2434061 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -22,7 +22,7 @@ void blk_mq_sched_insert_requests(struct request_queue *q, struct blk_mq_ctx *ctx, struct list_head *list, bool run_queue_async); -void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx); +bool blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx); int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e); void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e); diff --git a/block/blk-mq.c b/block/blk-mq.c index 40cba1b..dcb4673 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1048,7 +1048,8 @@ static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx *hctx) return true; } -bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) +bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, + bool got_budget) { struct blk_mq_hw_ctx *hctx; struct request *rq; @@ -1057,6 +1058,8 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *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. */ @@ -1074,16 +1077,30 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) * The initial allocation attempt failed, so we need to * rerun the hardware queue when a tag is freed. */ - if (!blk_mq_dispatch_wait_add(hctx)) + if (!blk_mq_dispatch_wait_add(hctx)) { + if (got_budget) + blk_mq_put_dispatch_budget(hctx); break; + } /* * It's possible that a tag was freed in the window * between the allocation failure and adding the * hardware queue to the wait queue. */ - if (!blk_mq_get_driver_tag(rq, &hctx, false)) + if (!blk_mq_get_driver_tag(rq, &hctx, false)) { + if (got_budget) + blk_mq_put_dispatch_budget(hctx); + break; + } + } + + if (!got_budget) { + ret = blk_mq_get_dispatch_budget(hctx); + if (ret == BLK_STS_RESOURCE) break; + if (ret != BLK_STS_OK) + goto fail_rq; } list_del_init(&rq->queuelist); @@ -1111,6 +1128,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) break; } + fail_rq: if (unlikely(ret != BLK_STS_OK)) { errors++; blk_mq_end_request(rq, BLK_STS_IOERR); @@ -1169,6 +1187,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) { int srcu_idx; + bool run_queue; /* * We should be running this queue from one of the CPUs that @@ -1185,15 +1204,18 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { rcu_read_lock(); - blk_mq_sched_dispatch_requests(hctx); + run_queue = blk_mq_sched_dispatch_requests(hctx); rcu_read_unlock(); } else { might_sleep(); srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); - blk_mq_sched_dispatch_requests(hctx); + run_queue = blk_mq_sched_dispatch_requests(hctx); srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); } + + if (run_queue) + blk_mq_run_hw_queue(hctx, true); } /* @@ -1582,6 +1604,13 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, if (!blk_mq_get_driver_tag(rq, NULL, false)) goto insert; + ret = blk_mq_get_dispatch_budget(hctx); + if (ret == BLK_STS_RESOURCE) { + blk_mq_put_driver_tag(rq); + goto insert; + } else if (ret != BLK_STS_OK) + goto fail_rq; + new_cookie = request_to_qc_t(hctx, rq); /* @@ -1598,6 +1627,7 @@ static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, __blk_mq_requeue_request(rq); goto insert; default: + fail_rq: *cookie = BLK_QC_T_NONE; blk_mq_end_request(rq, ret); return; @@ -2582,6 +2612,9 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) if (!set->ops->queue_rq) return -EINVAL; + if (!set->ops->get_budget ^ !set->ops->put_budget) + return -EINVAL; + if (set->queue_depth > BLK_MQ_MAX_DEPTH) { pr_info("blk-mq: reduced tag depth to %u\n", BLK_MQ_MAX_DEPTH); diff --git a/block/blk-mq.h b/block/blk-mq.h index ef15b34..e413b73 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -30,7 +30,7 @@ void blk_mq_freeze_queue(struct request_queue *q); void blk_mq_free_queue(struct request_queue *q); int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr); void blk_mq_wake_waiters(struct request_queue *q); -bool blk_mq_dispatch_rq_list(struct request_queue *, struct list_head *); +bool blk_mq_dispatch_rq_list(struct request_queue *, struct list_head *, bool); void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list); bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx); bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, @@ -137,4 +137,22 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx) void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part, unsigned int inflight[2]); +static inline void blk_mq_put_dispatch_budget(struct blk_mq_hw_ctx *hctx) +{ + struct request_queue *q = hctx->queue; + + if (q->mq_ops->put_budget) + q->mq_ops->put_budget(hctx); +} + +static inline blk_status_t blk_mq_get_dispatch_budget( + struct blk_mq_hw_ctx *hctx) +{ + struct request_queue *q = hctx->queue; + + if (q->mq_ops->get_budget) + return q->mq_ops->get_budget(hctx); + return BLK_STS_OK; +} + #endif diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 50c6485..901457df 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -90,6 +90,8 @@ struct blk_mq_queue_data { typedef blk_status_t (queue_rq_fn)(struct blk_mq_hw_ctx *, const struct blk_mq_queue_data *); +typedef blk_status_t (get_budget_fn)(struct blk_mq_hw_ctx *); +typedef void (put_budget_fn)(struct blk_mq_hw_ctx *); typedef enum blk_eh_timer_return (timeout_fn)(struct request *, bool); typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int); typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int); @@ -112,6 +114,15 @@ struct blk_mq_ops { queue_rq_fn *queue_rq; /* + * Reserve budget before queue request, once .queue_rq is + * run, it is driver's responsibility to release the + * reserved budget. Also we have to handle failure case + * of .get_budget for avoiding I/O deadlock. + */ + get_budget_fn *get_budget; + put_budget_fn *put_budget; + + /* * Called on request timeout */ timeout_fn *timeout; |
