diff options
| -rw-r--r-- | block/mq-deadline-main.c | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/block/mq-deadline-main.c b/block/mq-deadline-main.c index 58a401ea8f56..4815e536091f 100644 --- a/block/mq-deadline-main.c +++ b/block/mq-deadline-main.c @@ -32,6 +32,11 @@ */ static const int read_expire = HZ / 2; /* max time before a read is submitted. */ static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */ +/* + * Time after which to dispatch lower priority requests even if higher + * priority requests are pending. + */ +static const int aging_expire = 10 * HZ; static const int writes_starved = 2; /* max times reads can starve a write */ static const int fifo_batch = 16; /* # of sequential requests treated as one by the above parameters. For throughput. */ @@ -94,6 +99,7 @@ struct deadline_data { int writes_starved; int front_merges; u32 async_depth; + int aging_expire; spinlock_t lock; spinlock_t zone_lock; @@ -361,10 +367,11 @@ deadline_next_request(struct deadline_data *dd, struct dd_per_prio *per_prio, /* * deadline_dispatch_requests selects the best request according to - * read/write expire, fifo_batch, etc + * read/write expire, fifo_batch, etc and with a start time <= @latest. */ static struct request *__dd_dispatch_request(struct deadline_data *dd, - struct dd_per_prio *per_prio) + struct dd_per_prio *per_prio, + u64 latest_start_ns) { struct request *rq, *next_rq; enum dd_data_dir data_dir; @@ -377,6 +384,8 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd, if (!list_empty(&per_prio->dispatch)) { rq = list_first_entry(&per_prio->dispatch, struct request, queuelist); + if (rq->start_time_ns > latest_start_ns) + return NULL; list_del_init(&rq->queuelist); goto done; } @@ -454,6 +463,8 @@ dispatch_find_request: dd->batching = 0; dispatch_request: + if (rq->start_time_ns > latest_start_ns) + return NULL; /* * rq is the selected appropriate request. */ @@ -484,15 +495,32 @@ done: static struct request *dd_dispatch_request(struct blk_mq_hw_ctx *hctx) { struct deadline_data *dd = hctx->queue->elevator->elevator_data; - struct request *rq; + const u64 now_ns = ktime_get_ns(); + struct request *rq = NULL; enum dd_prio prio; spin_lock(&dd->lock); - for (prio = 0; prio <= DD_PRIO_MAX; prio++) { - rq = __dd_dispatch_request(dd, &dd->per_prio[prio]); + /* + * Start with dispatching requests whose deadline expired more than + * aging_expire jiffies ago. + */ + for (prio = DD_BE_PRIO; prio <= DD_PRIO_MAX; prio++) { + rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now_ns - + jiffies_to_nsecs(dd->aging_expire)); if (rq) + goto unlock; + } + /* + * Next, dispatch requests in priority order. Ignore lower priority + * requests if any higher priority requests are pending. + */ + for (prio = 0; prio <= DD_PRIO_MAX; prio++) { + rq = __dd_dispatch_request(dd, &dd->per_prio[prio], now_ns); + if (rq || dd_queued(dd, prio)) break; } + +unlock: spin_unlock(&dd->lock); return rq; @@ -603,6 +631,7 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e) dd->front_merges = 1; dd->last_dir = DD_WRITE; dd->fifo_batch = fifo_batch; + dd->aging_expire = aging_expire; spin_lock_init(&dd->lock); spin_lock_init(&dd->zone_lock); @@ -835,6 +864,7 @@ static ssize_t __FUNC(struct elevator_queue *e, char *page) \ #define SHOW_JIFFIES(__FUNC, __VAR) SHOW_INT(__FUNC, jiffies_to_msecs(__VAR)) SHOW_JIFFIES(deadline_read_expire_show, dd->fifo_expire[DD_READ]); SHOW_JIFFIES(deadline_write_expire_show, dd->fifo_expire[DD_WRITE]); +SHOW_JIFFIES(deadline_aging_expire_show, dd->aging_expire); SHOW_INT(deadline_writes_starved_show, dd->writes_starved); SHOW_INT(deadline_front_merges_show, dd->front_merges); SHOW_INT(deadline_async_depth_show, dd->front_merges); @@ -864,6 +894,7 @@ static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, msecs_to_jiffies) STORE_JIFFIES(deadline_read_expire_store, &dd->fifo_expire[DD_READ], 0, INT_MAX); STORE_JIFFIES(deadline_write_expire_store, &dd->fifo_expire[DD_WRITE], 0, INT_MAX); +STORE_JIFFIES(deadline_aging_expire_store, &dd->aging_expire, 0, INT_MAX); STORE_INT(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX); STORE_INT(deadline_front_merges_store, &dd->front_merges, 0, 1); STORE_INT(deadline_async_depth_store, &dd->front_merges, 1, INT_MAX); @@ -882,6 +913,7 @@ static struct elv_fs_entry deadline_attrs[] = { DD_ATTR(front_merges), DD_ATTR(async_depth), DD_ATTR(fifo_batch), + DD_ATTR(aging_expire), __ATTR_NULL }; |