diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 98eb02d32e6e..2ae78b31e4c0 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -21,6 +21,7 @@ #include <linux/delay.h> #include <linux/wait.h> #include <linux/kthread.h> +#include <linux/elevator.h> /* for rq_end_sector() */ #include <trace/events/block.h> @@ -216,6 +217,10 @@ struct mapped_device { struct kthread_worker kworker; struct task_struct *kworker_task; + + /* for request-based merge heuristic in dm_request_fn() */ + sector_t last_rq_pos; + int last_rq_rw; }; /* @@ -1930,6 +1935,9 @@ static void dm_start_request(struct mapped_device *md, struct request *orig) blk_start_request(orig); atomic_inc(&md->pending[rq_data_dir(orig)]); + md->last_rq_pos = rq_end_sector(orig); + md->last_rq_rw = rq_data_dir(orig); + /* * Hold the md reference here for the in-flight I/O. * We can't rely on the reference count by device opener, @@ -1982,6 +1990,10 @@ static void dm_request_fn(struct request_queue *q) continue; } + if (md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 && + md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) + goto delay_and_out; + if (ti->type->busy && ti->type->busy(ti)) goto delay_and_out; |