1 files changed, 29 insertions, 43 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 1b2d12cda43e..1ca813b16e78 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -134,13 +134,8 @@ struct cfq_data {
         struct rb_root prio_trees[CFQ_PRIO_LISTS];
 
         unsigned int busy_queues;
-        /*
-         * Used to track any pending rt requests so we can pre-empt current
-         * non-RT cfqq in service when this value is non-zero.
-         */
-        unsigned int busy_rt_queues;
 
-        int rq_in_driver;
+        int rq_in_driver[2];
         int sync_flight;
 
         /*
@@ -191,7 +186,6 @@ enum cfqq_state_flags {
         CFQ_CFQQ_FLAG_on_rr = 0,        /* on round-robin busy list */
         CFQ_CFQQ_FLAG_wait_request,     /* waiting for a request */
         CFQ_CFQQ_FLAG_must_dispatch,    /* must be allowed a dispatch */
-        CFQ_CFQQ_FLAG_must_alloc,       /* must be allowed rq alloc */
         CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
         CFQ_CFQQ_FLAG_fifo_expire,      /* FIFO checked in this slice */
         CFQ_CFQQ_FLAG_idle_window,      /* slice idling enabled */
@@ -218,7 +212,6 @@ static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq)		\
 CFQ_CFQQ_FNS(on_rr);
 CFQ_CFQQ_FNS(wait_request);
 CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(must_alloc);
 CFQ_CFQQ_FNS(must_alloc_slice);
 CFQ_CFQQ_FNS(fifo_expire);
 CFQ_CFQQ_FNS(idle_window);
@@ -239,6 +232,11 @@ static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
 static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
                                                 struct io_context *);
 
+static inline int rq_in_driver(struct cfq_data *cfqd)
+{
+        return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1];
+}
+
 static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
                                             int is_sync)
 {
@@ -257,7 +255,7 @@ static inline void cic_set_cfqq(struct cfq_io_context *cic,
  */
 static inline int cfq_bio_sync(struct bio *bio)
 {
-        if (bio_data_dir(bio) == READ || bio_sync(bio))
+        if (bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO))
                 return 1;
 
         return 0;
@@ -648,8 +646,6 @@ static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
         BUG_ON(cfq_cfqq_on_rr(cfqq));
         cfq_mark_cfqq_on_rr(cfqq);
         cfqd->busy_queues++;
-        if (cfq_class_rt(cfqq))
-                cfqd->busy_rt_queues++;
 
         cfq_resort_rr_list(cfqd, cfqq);
 }
@@ -673,8 +669,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 
         BUG_ON(!cfqd->busy_queues);
         cfqd->busy_queues--;
-        if (cfq_class_rt(cfqq))
-                cfqd->busy_rt_queues--;
 }
 
 /*
@@ -760,9 +754,9 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq)
 {
         struct cfq_data *cfqd = q->elevator->elevator_data;
 
-        cfqd->rq_in_driver++;
+        cfqd->rq_in_driver[rq_is_sync(rq)]++;
         cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
-                                                cfqd->rq_in_driver);
+                                                rq_in_driver(cfqd));
 
         cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
 }
@@ -770,11 +764,12 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq)
 static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
 {
         struct cfq_data *cfqd = q->elevator->elevator_data;
+        const int sync = rq_is_sync(rq);
 
-        WARN_ON(!cfqd->rq_in_driver);
-        cfqd->rq_in_driver--;
+        WARN_ON(!cfqd->rq_in_driver[sync]);
+        cfqd->rq_in_driver[sync]--;
         cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
-                                                cfqd->rq_in_driver);
+                                                rq_in_driver(cfqd));
 }
 
 static void cfq_remove_request(struct request *rq)
@@ -1080,7 +1075,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
         /*
          * still requests with the driver, don't idle
          */
-        if (cfqd->rq_in_driver)
+        if (rq_in_driver(cfqd))
                 return;
 
         /*
@@ -1115,6 +1110,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
 
         cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
 
+        cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
         cfq_remove_request(rq);
         cfqq->dispatched++;
         elv_dispatch_sort(q, rq);
@@ -1179,20 +1175,6 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
                 goto expire;
 
         /*
-         * If we have a RT cfqq waiting, then we pre-empt the current non-rt
-         * cfqq.
-         */
-        if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
-                /*
-                 * We simulate this as cfqq timed out so that it gets to bank
-                 * the remaining of its time slice.
-                 */
-                cfq_log_cfqq(cfqd, cfqq, "preempt");
-                cfq_slice_expired(cfqd, 1);
-                goto new_queue;
-        }
-
-        /*
          * The active queue has requests and isn't expired, allow it to
          * dispatch.
          */
@@ -1312,6 +1294,12 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
                 return 0;
 
         /*
+         * Drain async requests before we start sync IO
+         */
+        if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
+                return 0;
+
+        /*
          * If this is an async queue and we have sync IO in flight, let it wait
          */
         if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
@@ -1362,7 +1350,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
                 cfq_slice_expired(cfqd, 0);
         }
 
-        cfq_log(cfqd, "dispatched a request");
+        cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
         return 1;
 }
 
@@ -2130,11 +2118,11 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
  */
 static void cfq_update_hw_tag(struct cfq_data *cfqd)
 {
-        if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
-                cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+        if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak)
+                cfqd->rq_in_driver_peak = rq_in_driver(cfqd);
 
         if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
-            cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+            rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN)
                 return;
 
         if (cfqd->hw_tag_samples++ < 50)
@@ -2161,9 +2149,9 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 
         cfq_update_hw_tag(cfqd);
 
-        WARN_ON(!cfqd->rq_in_driver);
+        WARN_ON(!cfqd->rq_in_driver[sync]);
         WARN_ON(!cfqq->dispatched);
-        cfqd->rq_in_driver--;
+        cfqd->rq_in_driver[sync]--;
         cfqq->dispatched--;
 
         if (cfq_cfqq_sync(cfqq))
@@ -2197,7 +2185,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
                         cfq_arm_slice_timer(cfqd);
         }
 
-        if (!cfqd->rq_in_driver)
+        if (!rq_in_driver(cfqd))
                 cfq_schedule_dispatch(cfqd);
 }
 
@@ -2229,8 +2217,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
 
 static inline int __cfq_may_queue(struct cfq_queue *cfqq)
 {
-        if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
-            !cfq_cfqq_must_alloc_slice(cfqq)) {
+        if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
                 cfq_mark_cfqq_must_alloc_slice(cfqq);
                 return ELV_MQUEUE_MUST;
         }
@@ -2317,7 +2304,6 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
         }
 
         cfqq->allocated[rw]++;
-        cfq_clear_cfqq_must_alloc(cfqq);
         atomic_inc(&cfqq->ref);
 
         spin_unlock_irqrestore(q->queue_lock, flags);