X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=block%2Fblk-mq.c;h=a9354835cf5177cc5f14bec92e754202a918d30e;hb=429fba106e82e2792010a825b9dbeadd00bf9e9c;hp=70b210a308c452b43abd1a270e759f5e331ab55f;hpb=a75eda7bce5e8ffdebe6ddfe513b31e5ec3527d2;p=linux.git diff --git a/block/blk-mq.c b/block/blk-mq.c index 70b210a308c4..a9354835cf51 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -59,7 +59,8 @@ static int blk_mq_poll_stats_bkt(const struct request *rq) } /* - * Check if any of the ctx's have pending work in this hardware queue + * Check if any of the ctx, dispatch list or elevator + * have pending work in this hardware queue. */ static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) { @@ -1071,7 +1072,13 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); spin_lock(&hctx->dispatch_wait_lock); - list_del_init(&wait->entry); + if (!list_empty(&wait->entry)) { + struct sbitmap_queue *sbq; + + list_del_init(&wait->entry); + sbq = &hctx->tags->bitmap_tags; + atomic_dec(&sbq->ws_active); + } spin_unlock(&hctx->dispatch_wait_lock); blk_mq_run_hw_queue(hctx, true); @@ -1087,6 +1094,7 @@ static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, struct request *rq) { + struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags; struct wait_queue_head *wq; wait_queue_entry_t *wait; bool ret; @@ -1109,7 +1117,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, if (!list_empty_careful(&wait->entry)) return false; - wq = &bt_wait_ptr(&hctx->tags->bitmap_tags, hctx)->wait; + wq = &bt_wait_ptr(sbq, hctx)->wait; spin_lock_irq(&wq->lock); spin_lock(&hctx->dispatch_wait_lock); @@ -1119,6 +1127,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, return false; } + atomic_inc(&sbq->ws_active); wait->flags &= ~WQ_FLAG_EXCLUSIVE; __add_wait_queue(wq, wait); @@ -1139,6 +1148,7 @@ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, * someone else gets the wakeup. */ list_del_init(&wait->entry); + atomic_dec(&sbq->ws_active); spin_unlock(&hctx->dispatch_wait_lock); spin_unlock_irq(&wq->lock); @@ -1701,11 +1711,12 @@ void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) unsigned int depth; list_splice_init(&plug->mq_list, &list); - plug->rq_count = 0; if (plug->rq_count > 2 && plug->multiple_queues) list_sort(NULL, &list, plug_rq_cmp); + plug->rq_count = 0; + this_q = NULL; this_hctx = NULL; this_ctx = NULL; @@ -1790,74 +1801,76 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, return ret; } -blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, +static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie, - bool bypass, bool last) + bool bypass_insert, bool last) { struct request_queue *q = rq->q; bool run_queue = true; - blk_status_t ret = BLK_STS_RESOURCE; - int srcu_idx; - bool force = false; - hctx_lock(hctx, &srcu_idx); /* - * hctx_lock is needed before checking quiesced flag. + * RCU or SRCU read lock is needed before checking quiesced flag. * - * When queue is stopped or quiesced, ignore 'bypass', insert - * and return BLK_STS_OK to caller, and avoid driver to try to - * dispatch again. + * When queue is stopped or quiesced, ignore 'bypass_insert' from + * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, + * and avoid driver to try to dispatch again. */ - if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) { + if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { run_queue = false; - bypass = false; - goto out_unlock; + bypass_insert = false; + goto insert; } - if (unlikely(q->elevator && !bypass)) - goto out_unlock; + if (q->elevator && !bypass_insert) + goto insert; if (!blk_mq_get_dispatch_budget(hctx)) - goto out_unlock; + goto insert; if (!blk_mq_get_driver_tag(rq)) { blk_mq_put_dispatch_budget(hctx); - goto out_unlock; + goto insert; } - /* - * Always add a request that has been through - *.queue_rq() to the hardware dispatch list. - */ - force = true; - ret = __blk_mq_issue_directly(hctx, rq, cookie, last); -out_unlock: + return __blk_mq_issue_directly(hctx, rq, cookie, last); +insert: + if (bypass_insert) + return BLK_STS_RESOURCE; + + blk_mq_request_bypass_insert(rq, run_queue); + return BLK_STS_OK; +} + +static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + struct request *rq, blk_qc_t *cookie) +{ + blk_status_t ret; + int srcu_idx; + + might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); + + hctx_lock(hctx, &srcu_idx); + + ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true); + if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) + blk_mq_request_bypass_insert(rq, true); + else if (ret != BLK_STS_OK) + blk_mq_end_request(rq, ret); + + hctx_unlock(hctx, srcu_idx); +} + +blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) +{ + blk_status_t ret; + int srcu_idx; + blk_qc_t unused_cookie; + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + hctx_lock(hctx, &srcu_idx); + ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last); hctx_unlock(hctx, srcu_idx); - switch (ret) { - case BLK_STS_OK: - break; - case BLK_STS_DEV_RESOURCE: - case BLK_STS_RESOURCE: - if (force) { - blk_mq_request_bypass_insert(rq, run_queue); - /* - * We have to return BLK_STS_OK for the DM - * to avoid livelock. Otherwise, we return - * the real result to indicate whether the - * request is direct-issued successfully. - */ - ret = bypass ? BLK_STS_OK : ret; - } else if (!bypass) { - blk_mq_sched_insert_request(rq, false, - run_queue, false); - } - break; - default: - if (!bypass) - blk_mq_end_request(rq, ret); - break; - } return ret; } @@ -1865,20 +1878,22 @@ blk_status_t blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, struct list_head *list) { - blk_qc_t unused; - blk_status_t ret = BLK_STS_OK; - while (!list_empty(list)) { + blk_status_t ret; struct request *rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); - if (ret == BLK_STS_OK) - ret = blk_mq_try_issue_directly(hctx, rq, &unused, - false, + ret = blk_mq_request_issue_directly(rq, list_empty(list)); + if (ret != BLK_STS_OK) { + if (ret == BLK_STS_RESOURCE || + ret == BLK_STS_DEV_RESOURCE) { + blk_mq_request_bypass_insert(rq, list_empty(list)); - else - blk_mq_sched_insert_request(rq, false, true, false); + break; + } + blk_mq_end_request(rq, ret); + } } /* @@ -1886,7 +1901,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, * the driver there was more coming, but that turned out to * be a lie. */ - if (ret != BLK_STS_OK && hctx->queue->mq_ops->commit_rqs) + if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs) hctx->queue->mq_ops->commit_rqs(hctx); } @@ -1993,19 +2008,21 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) plug->rq_count--; } blk_add_rq_to_plug(plug, rq); + trace_block_plug(q); blk_mq_put_ctx(data.ctx); if (same_queue_rq) { data.hctx = same_queue_rq->mq_hctx; + trace_block_unplug(q, 1, true); blk_mq_try_issue_directly(data.hctx, same_queue_rq, - &cookie, false, true); + &cookie); } } else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator && !data.hctx->dispatch_busy)) { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); - blk_mq_try_issue_directly(data.hctx, rq, &cookie, false, true); + blk_mq_try_issue_directly(data.hctx, rq, &cookie); } else { blk_mq_put_ctx(data.ctx); blk_mq_bio_to_request(rq, bio); @@ -2322,7 +2339,7 @@ static int blk_mq_init_hctx(struct request_queue *q, return 0; free_fq: - kfree(hctx->fq); + blk_free_flush_queue(hctx->fq); exit_hctx: if (set->ops->exit_hctx) set->ops->exit_hctx(hctx, hctx_idx);