diff options
| -rw-r--r-- | block/blk-mq-sched.c | 12 | ||||
| -rw-r--r-- | block/blk-mq.c | 2 | ||||
| -rw-r--r-- | block/blk-mq.h | 2 |
3 files changed, 14 insertions, 2 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 045b6878b8c5..a9182d2f8ad3 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -168,9 +168,19 @@ static int __blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) * in blk_mq_dispatch_rq_list(). */ list_add_tail(&rq->queuelist, &rq_list); + count++; if (rq->mq_hctx != hctx) multi_hctxs = true; - } while (++count < max_dispatch); + + /* + * If we cannot get tag for the request, stop dequeueing + * requests from the IO scheduler. We are unlikely to be able + * to submit them anyway and it creates false impression for + * scheduling heuristics that the device can take more IO. + */ + if (!blk_mq_get_driver_tag(rq)) + break; + } while (count < max_dispatch); if (!count) { if (run_queue) diff --git a/block/blk-mq.c b/block/blk-mq.c index f11d4018ce2e..4261adee9964 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1104,7 +1104,7 @@ static bool __blk_mq_get_driver_tag(struct request *rq) return true; } -static bool blk_mq_get_driver_tag(struct request *rq) +bool blk_mq_get_driver_tag(struct request *rq) { struct blk_mq_hw_ctx *hctx = rq->mq_hctx; diff --git a/block/blk-mq.h b/block/blk-mq.h index 556368d2c5b6..4b1ca7b7bbeb 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -260,6 +260,8 @@ static inline void blk_mq_put_driver_tag(struct request *rq) __blk_mq_put_driver_tag(rq->mq_hctx, rq); } +bool blk_mq_get_driver_tag(struct request *rq); + static inline void blk_mq_clear_mq_map(struct blk_mq_queue_map *qmap) { int cpu; |