X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=block%2Fcfq-iosched.c;h=c95c69e199f4cded3e9200c68756b8718bfda8d1;hb=aa6f6a3de18131348f70951efb2c56d806033e09;hp=fce8a749f4be8af3ffa7a584c3f97adf7fbf1bbd;hpb=8e2967555571659d2c8a70dd120710110ed7bba4;p=safe%2Fjmp%2Flinux-2.6

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index fce8a74..c95c69e 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -27,6 +27,8 @@ static const int cfq_slice_sync = HZ / 10;
 static int cfq_slice_async = HZ / 25;
 static const int cfq_slice_async_rq = 2;
 static int cfq_slice_idle = HZ / 125;
+static const int cfq_target_latency = HZ * 3/10; /* 300 ms */
+static const int cfq_hist_divisor = 4;
 
 /*
  * offset from end of service tree
@@ -38,6 +40,12 @@ static int cfq_slice_idle = HZ / 125;
  */
 #define CFQ_MIN_TT		(2)
 
+/*
+ * Allow merged cfqqs to perform this amount of seeky I/O before
+ * deciding to break the queues up again.
+ */
+#define CFQQ_COOP_TOUT		(HZ)
+
 #define CFQ_SLICE_SCALE		(5)
 #define CFQ_HW_QUEUE_MIN	(5)
 
@@ -67,8 +75,9 @@ static DEFINE_SPINLOCK(ioc_gone_lock);
 struct cfq_rb_root {
 	struct rb_root rb;
 	struct rb_node *left;
+	unsigned count;
 };
-#define CFQ_RB_ROOT	(struct cfq_rb_root) { RB_ROOT, NULL, }
+#define CFQ_RB_ROOT	(struct cfq_rb_root) { RB_ROOT, NULL, 0, }
 
 /*
  * Per process-grouping structure
@@ -112,7 +121,16 @@ struct cfq_queue {
 	unsigned short ioprio, org_ioprio;
 	unsigned short ioprio_class, org_ioprio_class;
 
+	unsigned int seek_samples;
+	u64 seek_total;
+	sector_t seek_mean;
+	sector_t last_request_pos;
+	unsigned long seeky_start;
+
 	pid_t pid;
+
+	struct cfq_rb_root *service_tree;
+	struct cfq_queue *new_cfqq;
 };
 
 /*
@@ -134,6 +152,8 @@ struct cfq_data {
 	struct rb_root prio_trees[CFQ_PRIO_LISTS];
 
 	unsigned int busy_queues;
+	unsigned int busy_rt_queues;
+	unsigned int busy_queues_avg[2];
 
 	int rq_in_driver[2];
 	int sync_flight;
@@ -150,7 +170,7 @@ struct cfq_data {
 	 * idle window management
 	 */
 	struct timer_list idle_slice_timer;
-	struct delayed_work unplug_work;
+	struct work_struct unplug_work;
 
 	struct cfq_queue *active_queue;
 	struct cfq_io_context *active_cic;
@@ -173,7 +193,7 @@ struct cfq_data {
 	unsigned int cfq_slice[2];
 	unsigned int cfq_slice_async_rq;
 	unsigned int cfq_slice_idle;
-	unsigned int cfq_desktop;
+	unsigned int cfq_latency;
 
 	struct list_head cic_list;
 
@@ -195,7 +215,7 @@ enum cfqq_state_flags {
 	CFQ_CFQQ_FLAG_prio_changed,	/* task priority has changed */
 	CFQ_CFQQ_FLAG_slice_new,	/* no requests dispatched in slice */
 	CFQ_CFQQ_FLAG_sync,		/* synchronous queue */
-	CFQ_CFQQ_FLAG_coop,		/* has done a coop jump of the queue */
+	CFQ_CFQQ_FLAG_coop,		/* cfqq is shared */
 };
 
 #define CFQ_CFQQ_FNS(name)						\
@@ -230,7 +250,7 @@ CFQ_CFQQ_FNS(coop);
 	blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
 
 static void cfq_dispatch_insert(struct request_queue *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
+static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
 				       struct io_context *, gfp_t);
 static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
 						struct io_context *);
@@ -241,40 +261,35 @@ static inline int rq_in_driver(struct cfq_data *cfqd)
 }
 
 static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
-					    int is_sync)
+					    bool is_sync)
 {
-	return cic->cfqq[!!is_sync];
+	return cic->cfqq[is_sync];
 }
 
 static inline void cic_set_cfqq(struct cfq_io_context *cic,
-				struct cfq_queue *cfqq, int is_sync)
+				struct cfq_queue *cfqq, bool is_sync)
 {
-	cic->cfqq[!!is_sync] = cfqq;
+	cic->cfqq[is_sync] = cfqq;
 }
 
 /*
  * We regard a request as SYNC, if it's either a read or has the SYNC bit
  * set (in which case it could also be direct WRITE).
  */
-static inline int cfq_bio_sync(struct bio *bio)
+static inline bool cfq_bio_sync(struct bio *bio)
 {
-	if (bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO))
-		return 1;
-
-	return 0;
+	return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO);
 }
 
 /*
  * scheduler run of queue, if there are requests pending and no one in the
  * driver that will restart queueing
  */
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd,
-					 unsigned long delay)
+static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
 {
 	if (cfqd->busy_queues) {
 		cfq_log(cfqd, "schedule dispatch");
-		kblockd_schedule_delayed_work(cfqd->queue, &cfqd->unplug_work,
-						delay);
+		kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
 	}
 }
 
@@ -290,7 +305,7 @@ static int cfq_queue_empty(struct request_queue *q)
  * if a queue is marked sync and has sync io queued. A sync queue with async
  * io only, should not get full sync slice length.
  */
-static inline int cfq_prio_slice(struct cfq_data *cfqd, int sync,
+static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync,
 				 unsigned short prio)
 {
 	const int base_slice = cfqd->cfq_slice[sync];
@@ -306,10 +321,52 @@ cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
 }
 
+/*
+ * get averaged number of queues of RT/BE priority.
+ * average is updated, with a formula that gives more weight to higher numbers,
+ * to quickly follows sudden increases and decrease slowly
+ */
+
+static inline unsigned
+cfq_get_avg_queues(struct cfq_data *cfqd, bool rt) {
+	unsigned min_q, max_q;
+	unsigned mult  = cfq_hist_divisor - 1;
+	unsigned round = cfq_hist_divisor / 2;
+	unsigned busy = cfqd->busy_rt_queues;
+
+	if (!rt)
+		busy = cfqd->busy_queues - cfqd->busy_rt_queues;
+
+	min_q = min(cfqd->busy_queues_avg[rt], busy);
+	max_q = max(cfqd->busy_queues_avg[rt], busy);
+	cfqd->busy_queues_avg[rt] = (mult * max_q + min_q + round) /
+		cfq_hist_divisor;
+	return cfqd->busy_queues_avg[rt];
+}
+
 static inline void
 cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+	unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
+	if (cfqd->cfq_latency) {
+		/* interested queues (we consider only the ones with the same
+		 * priority class) */
+		unsigned iq = cfq_get_avg_queues(cfqd, cfq_class_rt(cfqq));
+		unsigned sync_slice = cfqd->cfq_slice[1];
+		unsigned expect_latency = sync_slice * iq;
+		if (expect_latency > cfq_target_latency) {
+			unsigned base_low_slice = 2 * cfqd->cfq_slice_idle;
+			/* scale low_slice according to IO priority
+			 * and sync vs async */
+			unsigned low_slice =
+				min(slice, base_low_slice * slice / sync_slice);
+			/* the adapted slice value is scaled to fit all iqs
+			 * into the target latency */
+			slice = max(slice * cfq_target_latency / expect_latency,
+				    low_slice);
+		}
+	}
+	cfqq->slice_end = jiffies + slice;
 	cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
 }
 
@@ -318,7 +375,7 @@ cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
  * isn't valid until the first request from the dispatch is activated
  * and the slice time set.
  */
-static inline int cfq_slice_used(struct cfq_queue *cfqq)
+static inline bool cfq_slice_used(struct cfq_queue *cfqq)
 {
 	if (cfq_cfqq_slice_new(cfqq))
 		return 0;
@@ -448,6 +505,7 @@ static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
 	if (root->left == n)
 		root->left = NULL;
 	rb_erase_init(n, &root->rb);
+	--root->count;
 }
 
 /*
@@ -493,27 +551,37 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
  * we will service the queues.
  */
 static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-				 int add_front)
+				 bool add_front)
 {
 	struct rb_node **p, *parent;
 	struct cfq_queue *__cfqq;
 	unsigned long rb_key;
+	struct cfq_rb_root *service_tree = &cfqd->service_tree;
 	int left;
 
 	if (cfq_class_idle(cfqq)) {
 		rb_key = CFQ_IDLE_DELAY;
-		parent = rb_last(&cfqd->service_tree.rb);
+		parent = rb_last(&service_tree->rb);
 		if (parent && parent != &cfqq->rb_node) {
 			__cfqq = rb_entry(parent, struct cfq_queue, rb_node);
 			rb_key += __cfqq->rb_key;
 		} else
 			rb_key += jiffies;
 	} else if (!add_front) {
+		/*
+		 * Get our rb key offset. Subtract any residual slice
+		 * value carried from last service. A negative resid
+		 * count indicates slice overrun, and this should position
+		 * the next service time further away in the tree.
+		 */
 		rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
-		rb_key += cfqq->slice_resid;
+		rb_key -= cfqq->slice_resid;
 		cfqq->slice_resid = 0;
-	} else
-		rb_key = 0;
+	} else {
+		rb_key = -HZ;
+		__cfqq = cfq_rb_first(service_tree);
+		rb_key += __cfqq ? __cfqq->rb_key : jiffies;
+	}
 
 	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
 		/*
@@ -522,12 +590,14 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		if (rb_key == cfqq->rb_key)
 			return;
 
-		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
+		cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
+		cfqq->service_tree = NULL;
 	}
 
 	left = 1;
 	parent = NULL;
-	p = &cfqd->service_tree.rb.rb_node;
+	cfqq->service_tree = service_tree;
+	p = &service_tree->rb.rb_node;
 	while (*p) {
 		struct rb_node **n;
 
@@ -547,7 +617,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 			n = &(*p)->rb_left;
 		else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
 			n = &(*p)->rb_right;
-		else if (rb_key < __cfqq->rb_key)
+		else if (time_before(rb_key, __cfqq->rb_key))
 			n = &(*p)->rb_left;
 		else
 			n = &(*p)->rb_right;
@@ -559,11 +629,12 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	}
 
 	if (left)
-		cfqd->service_tree.left = &cfqq->rb_node;
+		service_tree->left = &cfqq->rb_node;
 
 	cfqq->rb_key = rb_key;
 	rb_link_node(&cfqq->rb_node, parent, p);
-	rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
+	rb_insert_color(&cfqq->rb_node, &service_tree->rb);
+	service_tree->count++;
 }
 
 static struct cfq_queue *
@@ -651,7 +722,8 @@ 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);
 }
 
@@ -665,8 +737,10 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 	BUG_ON(!cfq_cfqq_on_rr(cfqq));
 	cfq_clear_cfqq_on_rr(cfqq);
 
-	if (!RB_EMPTY_NODE(&cfqq->rb_node))
-		cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
+	if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
+		cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
+		cfqq->service_tree = NULL;
+	}
 	if (cfqq->p_root) {
 		rb_erase(&cfqq->p_node, cfqq->p_root);
 		cfqq->p_root = NULL;
@@ -674,6 +748,8 @@ 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--;
 }
 
 /*
@@ -827,8 +903,10 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
 	 * reposition in fifo if next is older than rq
 	 */
 	if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
-	    time_before(next->start_time, rq->start_time))
+	    time_before(rq_fifo_time(next), rq_fifo_time(rq))) {
 		list_move(&rq->queuelist, &next->queuelist);
+		rq_set_fifo_time(rq, rq_fifo_time(next));
+	}
 
 	cfq_remove_request(next);
 }
@@ -844,7 +922,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 	 * Disallow merge of a sync bio into an async request.
 	 */
 	if (cfq_bio_sync(bio) && !rq_is_sync(rq))
-		return 0;
+		return false;
 
 	/*
 	 * Lookup the cfqq that this bio will be queued with. Allow
@@ -852,13 +930,10 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
 	 */
 	cic = cfq_cic_lookup(cfqd, current->io_context);
 	if (!cic)
-		return 0;
+		return false;
 
 	cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
-	if (cfqq == RQ_CFQQ(rq))
-		return 1;
-
-	return 0;
+	return cfqq == RQ_CFQQ(rq);
 }
 
 static void __cfq_set_active_queue(struct cfq_data *cfqd,
@@ -886,7 +961,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
  */
 static void
 __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-		    int timed_out)
+		    bool timed_out)
 {
 	cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
 
@@ -914,7 +989,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	}
 }
 
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int timed_out)
+static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
 {
 	struct cfq_queue *cfqq = cfqd->active_queue;
 
@@ -940,11 +1015,8 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
 static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
 					      struct cfq_queue *cfqq)
 {
-	if (!cfqq) {
+	if (!cfqq)
 		cfqq = cfq_get_next_queue(cfqd);
-		if (cfqq)
-			cfq_clear_cfqq_coop(cfqq);
-	}
 
 	__cfq_set_active_queue(cfqd, cfqq);
 	return cfqq;
@@ -959,16 +1031,16 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
 		return cfqd->last_position - blk_rq_pos(rq);
 }
 
-#define CIC_SEEK_THR	8 * 1024
-#define CIC_SEEKY(cic)	((cic)->seek_mean > CIC_SEEK_THR)
+#define CFQQ_SEEK_THR		8 * 1024
+#define CFQQ_SEEKY(cfqq)	((cfqq)->seek_mean > CFQQ_SEEK_THR)
 
-static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
+static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+			       struct request *rq)
 {
-	struct cfq_io_context *cic = cfqd->active_cic;
-	sector_t sdist = cic->seek_mean;
+	sector_t sdist = cfqq->seek_mean;
 
-	if (!sample_valid(cic->seek_samples))
-		sdist = CIC_SEEK_THR;
+	if (!sample_valid(cfqq->seek_samples))
+		sdist = CFQQ_SEEK_THR;
 
 	return cfq_dist_from_last(cfqd, rq) <= sdist;
 }
@@ -997,7 +1069,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
 	 * will contain the closest sector.
 	 */
 	__cfqq = rb_entry(parent, struct cfq_queue, p_node);
-	if (cfq_rq_close(cfqd, __cfqq->next_rq))
+	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
 		return __cfqq;
 
 	if (blk_rq_pos(__cfqq->next_rq) < sector)
@@ -1008,7 +1080,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
 		return NULL;
 
 	__cfqq = rb_entry(node, struct cfq_queue, p_node);
-	if (cfq_rq_close(cfqd, __cfqq->next_rq))
+	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
 		return __cfqq;
 
 	return NULL;
@@ -1025,16 +1097,13 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
  * assumption.
  */
 static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
-					      struct cfq_queue *cur_cfqq,
-					      int probe)
+					      struct cfq_queue *cur_cfqq)
 {
 	struct cfq_queue *cfqq;
 
-	/*
-	 * A valid cfq_io_context is necessary to compare requests against
-	 * the seek_mean of the current cfqq.
-	 */
-	if (!cfqd->active_cic)
+	if (!cfq_cfqq_sync(cur_cfqq))
+		return NULL;
+	if (CFQQ_SEEKY(cur_cfqq))
 		return NULL;
 
 	/*
@@ -1046,11 +1115,14 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
 	if (!cfqq)
 		return NULL;
 
-	if (cfq_cfqq_coop(cfqq))
+	/*
+	 * It only makes sense to merge sync queues.
+	 */
+	if (!cfq_cfqq_sync(cfqq))
+		return NULL;
+	if (CFQQ_SEEKY(cfqq))
 		return NULL;
 
-	if (!probe)
-		cfq_mark_cfqq_coop(cfqq);
 	return cfqq;
 }
 
@@ -1090,6 +1162,15 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	if (!cic || !atomic_read(&cic->ioc->nr_tasks))
 		return;
 
+	/*
+	 * If our average think time is larger than the remaining time
+	 * slice, then don't idle. This avoids overrunning the allotted
+	 * time slice.
+	 */
+	if (sample_valid(cic->ttime_samples) &&
+	    (cfqq->slice_end - jiffies < cic->ttime_mean))
+		return;
+
 	cfq_mark_cfqq_wait_request(cfqq);
 
 	/*
@@ -1098,7 +1179,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
 	 * seeks. so allow a little bit of time for him to submit a new rq
 	 */
 	sl = cfqd->cfq_slice_idle;
-	if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
+	if (sample_valid(cfqq->seek_samples) && CFQQ_SEEKY(cfqq))
 		sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
 
 	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
@@ -1129,9 +1210,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
  */
 static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
 {
-	struct cfq_data *cfqd = cfqq->cfqd;
-	struct request *rq;
-	int fifo;
+	struct request *rq = NULL;
 
 	if (cfq_cfqq_fifo_expire(cfqq))
 		return NULL;
@@ -1141,13 +1220,11 @@ static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
 	if (list_empty(&cfqq->fifo))
 		return NULL;
 
-	fifo = cfq_cfqq_sync(cfqq);
 	rq = rq_entry_fifo(cfqq->fifo.next);
-
-	if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
+	if (time_before(jiffies, rq_fifo_time(rq)))
 		rq = NULL;
 
-	cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq);
+	cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
 	return rq;
 }
 
@@ -1162,6 +1239,52 @@ cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 }
 
 /*
+ * Must be called with the queue_lock held.
+ */
+static int cfqq_process_refs(struct cfq_queue *cfqq)
+{
+	int process_refs, io_refs;
+
+	io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
+	process_refs = atomic_read(&cfqq->ref) - io_refs;
+	BUG_ON(process_refs < 0);
+	return process_refs;
+}
+
+static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
+{
+	int process_refs, new_process_refs;
+	struct cfq_queue *__cfqq;
+
+	/* Avoid a circular list and skip interim queue merges */
+	while ((__cfqq = new_cfqq->new_cfqq)) {
+		if (__cfqq == cfqq)
+			return;
+		new_cfqq = __cfqq;
+	}
+
+	process_refs = cfqq_process_refs(cfqq);
+	/*
+	 * If the process for the cfqq has gone away, there is no
+	 * sense in merging the queues.
+	 */
+	if (process_refs == 0)
+		return;
+
+	/*
+	 * Merge in the direction of the lesser amount of work.
+	 */
+	new_process_refs = cfqq_process_refs(new_cfqq);
+	if (new_process_refs >= process_refs) {
+		cfqq->new_cfqq = new_cfqq;
+		atomic_add(process_refs, &new_cfqq->ref);
+	} else {
+		new_cfqq->new_cfqq = cfqq;
+		atomic_add(new_process_refs, &cfqq->ref);
+	}
+}
+
+/*
  * Select a queue for service. If we have a current active queue,
  * check whether to continue servicing it, or retrieve and set a new one.
  */
@@ -1190,11 +1313,14 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
 	 * If another queue has a request waiting within our mean seek
 	 * distance, let it run.  The expire code will check for close
 	 * cooperators and put the close queue at the front of the service
-	 * tree.
+	 * tree.  If possible, merge the expiring queue with the new cfqq.
 	 */
-	new_cfqq = cfq_close_cooperator(cfqd, cfqq, 0);
-	if (new_cfqq)
+	new_cfqq = cfq_close_cooperator(cfqd, cfqq);
+	if (new_cfqq) {
+		if (!cfqq->new_cfqq)
+			cfq_setup_merge(cfqq, new_cfqq);
 		goto expire;
+	}
 
 	/*
 	 * No requests pending. If the active queue still has requests in
@@ -1248,67 +1374,21 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
 	return dispatched;
 }
 
-/*
- * Dispatch a request from cfqq, moving them to the request queue
- * dispatch list.
- */
-static void cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
-	struct request *rq;
-
-	BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
-
-	/*
-	 * follow expired path, else get first next available
-	 */
-	rq = cfq_check_fifo(cfqq);
-	if (!rq)
-		rq = cfqq->next_rq;
-
-	/*
-	 * insert request into driver dispatch list
-	 */
-	cfq_dispatch_insert(cfqd->queue, rq);
-
-	if (!cfqd->active_cic) {
-		struct cfq_io_context *cic = RQ_CIC(rq);
-
-		atomic_long_inc(&cic->ioc->refcount);
-		cfqd->active_cic = cic;
-	}
-}
-
-/*
- * Find the cfqq that we need to service and move a request from that to the
- * dispatch list
- */
-static int cfq_dispatch_requests(struct request_queue *q, int force)
+static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
-	struct cfq_data *cfqd = q->elevator->elevator_data;
-	struct cfq_queue *cfqq;
 	unsigned int max_dispatch;
 
-	if (!cfqd->busy_queues)
-		return 0;
-
-	if (unlikely(force))
-		return cfq_forced_dispatch(cfqd);
-
-	cfqq = cfq_select_queue(cfqd);
-	if (!cfqq)
-		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;
+		return false;
 
 	/*
 	 * If this is an async queue and we have sync IO in flight, let it wait
 	 */
 	if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
-		return 0;
+		return false;
 
 	max_dispatch = cfqd->cfq_quantum;
 	if (cfq_class_idle(cfqq))
@@ -1322,13 +1402,13 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
 		 * idle queue must always only have a single IO in flight
 		 */
 		if (cfq_class_idle(cfqq))
-			return 0;
+			return false;
 
 		/*
 		 * We have other queues, don't allow more IO from this one
 		 */
 		if (cfqd->busy_queues > 1)
-			return 0;
+			return false;
 
 		/*
 		 * Sole queue user, allow bigger slice
@@ -1341,30 +1421,83 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
 	 * We also ramp up the dispatch depth gradually for async IO,
 	 * based on the last sync IO we serviced
 	 */
-	if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_desktop) {
+	if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
 		unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
 		unsigned int depth;
 
-		/*
-		 * must wait a bit longer
-		 */
-		if (last_sync < cfq_slice_sync) {
-			cfq_schedule_dispatch(cfqd, cfq_slice_sync - last_sync);
-			return 0;
-		}
-
-		depth = last_sync / cfq_slice_sync;
+		depth = last_sync / cfqd->cfq_slice[1];
+		if (!depth && !cfqq->dispatched)
+			depth = 1;
 		if (depth < max_dispatch)
 			max_dispatch = depth;
 	}
 
-	if (cfqq->dispatched >= max_dispatch)
+	/*
+	 * If we're below the current max, allow a dispatch
+	 */
+	return cfqq->dispatched < max_dispatch;
+}
+
+/*
+ * Dispatch a request from cfqq, moving them to the request queue
+ * dispatch list.
+ */
+static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+	struct request *rq;
+
+	BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
+
+	if (!cfq_may_dispatch(cfqd, cfqq))
+		return false;
+
+	/*
+	 * follow expired path, else get first next available
+	 */
+	rq = cfq_check_fifo(cfqq);
+	if (!rq)
+		rq = cfqq->next_rq;
+
+	/*
+	 * insert request into driver dispatch list
+	 */
+	cfq_dispatch_insert(cfqd->queue, rq);
+
+	if (!cfqd->active_cic) {
+		struct cfq_io_context *cic = RQ_CIC(rq);
+
+		atomic_long_inc(&cic->ioc->refcount);
+		cfqd->active_cic = cic;
+	}
+
+	return true;
+}
+
+/*
+ * Find the cfqq that we need to service and move a request from that to the
+ * dispatch list
+ */
+static int cfq_dispatch_requests(struct request_queue *q, int force)
+{
+	struct cfq_data *cfqd = q->elevator->elevator_data;
+	struct cfq_queue *cfqq;
+
+	if (!cfqd->busy_queues)
+		return 0;
+
+	if (unlikely(force))
+		return cfq_forced_dispatch(cfqd);
+
+	cfqq = cfq_select_queue(cfqd);
+	if (!cfqq)
 		return 0;
 
 	/*
-	 * Dispatch a request from this cfqq
+	 * Dispatch a request from this cfqq, if it is allowed
 	 */
-	cfq_dispatch_request(cfqd, cfqq);
+	if (!cfq_dispatch_request(cfqd, cfqq))
+		return 0;
+
 	cfqq->slice_dispatch++;
 	cfq_clear_cfqq_must_dispatch(cfqq);
 
@@ -1405,7 +1538,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
 
 	if (unlikely(cfqd->active_queue == cfqq)) {
 		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd, 0);
+		cfq_schedule_dispatch(cfqd);
 	}
 
 	kmem_cache_free(cfq_pool, cfqq);
@@ -1498,9 +1631,27 @@ static void cfq_free_io_context(struct io_context *ioc)
 
 static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 {
+	struct cfq_queue *__cfqq, *next;
+
 	if (unlikely(cfqq == cfqd->active_queue)) {
 		__cfq_slice_expired(cfqd, cfqq, 0);
-		cfq_schedule_dispatch(cfqd, 0);
+		cfq_schedule_dispatch(cfqd);
+	}
+
+	/*
+	 * If this queue was scheduled to merge with another queue, be
+	 * sure to drop the reference taken on that queue (and others in
+	 * the merge chain).  See cfq_setup_merge and cfq_merge_cfqqs.
+	 */
+	__cfqq = cfqq->new_cfqq;
+	while (__cfqq) {
+		if (__cfqq == cfqq) {
+			WARN(1, "cfqq->new_cfqq loop detected\n");
+			break;
+		}
+		next = __cfqq->new_cfqq;
+		cfq_put_queue(__cfqq);
+		__cfqq = next;
 	}
 
 	cfq_put_queue(cfqq);
@@ -1664,7 +1815,7 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
 }
 
 static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
-			  pid_t pid, int is_sync)
+			  pid_t pid, bool is_sync)
 {
 	RB_CLEAR_NODE(&cfqq->rb_node);
 	RB_CLEAR_NODE(&cfqq->p_node);
@@ -1684,7 +1835,7 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 }
 
 static struct cfq_queue *
-cfq_find_alloc_queue(struct cfq_data *cfqd, int is_sync,
+cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
 		     struct io_context *ioc, gfp_t gfp_mask)
 {
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
@@ -1748,7 +1899,7 @@ cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
 }
 
 static struct cfq_queue *
-cfq_get_queue(struct cfq_data *cfqd, int is_sync, struct io_context *ioc,
+cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
 	      gfp_t gfp_mask)
 {
 	const int ioprio = task_ioprio(ioc);
@@ -1932,33 +2083,46 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
 }
 
 static void
-cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,
+cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		       struct request *rq)
 {
 	sector_t sdist;
 	u64 total;
 
-	if (!cic->last_request_pos)
+	if (!cfqq->last_request_pos)
 		sdist = 0;
-	else if (cic->last_request_pos < blk_rq_pos(rq))
-		sdist = blk_rq_pos(rq) - cic->last_request_pos;
+	else if (cfqq->last_request_pos < blk_rq_pos(rq))
+		sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
 	else
-		sdist = cic->last_request_pos - blk_rq_pos(rq);
+		sdist = cfqq->last_request_pos - blk_rq_pos(rq);
 
 	/*
 	 * Don't allow the seek distance to get too large from the
 	 * odd fragment, pagein, etc
 	 */
-	if (cic->seek_samples <= 60) /* second&third seek */
-		sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);
+	if (cfqq->seek_samples <= 60) /* second&third seek */
+		sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024);
 	else
-		sdist = min(sdist, (cic->seek_mean * 4)	+ 2*1024*64);
+		sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64);
+
+	cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8;
+	cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8;
+	total = cfqq->seek_total + (cfqq->seek_samples/2);
+	do_div(total, cfqq->seek_samples);
+	cfqq->seek_mean = (sector_t)total;
 
-	cic->seek_samples = (7*cic->seek_samples + 256) / 8;
-	cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
-	total = cic->seek_total + (cic->seek_samples/2);
-	do_div(total, cic->seek_samples);
-	cic->seek_mean = (sector_t)total;
+	/*
+	 * If this cfqq is shared between multiple processes, check to
+	 * make sure that those processes are still issuing I/Os within
+	 * the mean seek distance.  If not, it may be time to break the
+	 * queues apart again.
+	 */
+	if (cfq_cfqq_coop(cfqq)) {
+		if (CFQQ_SEEKY(cfqq) && !cfqq->seeky_start)
+			cfqq->seeky_start = jiffies;
+		else if (!CFQQ_SEEKY(cfqq))
+			cfqq->seeky_start = 0;
+	}
 }
 
 /*
@@ -1980,10 +2144,13 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 	enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
 
 	if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
-	    (!cfqd->cfq_desktop && cfqd->hw_tag && CIC_SEEKY(cic)))
+	    (!cfqd->cfq_latency && cfqd->hw_tag && CFQQ_SEEKY(cfqq)))
 		enable_idle = 0;
 	else if (sample_valid(cic->ttime_samples)) {
-		if (cic->ttime_mean > cfqd->cfq_slice_idle)
+		unsigned int slice_idle = cfqd->cfq_slice_idle;
+		if (sample_valid(cfqq->seek_samples) && CFQQ_SEEKY(cfqq))
+			slice_idle = msecs_to_jiffies(CFQ_MIN_TT);
+		if (cic->ttime_mean > slice_idle)
 			enable_idle = 0;
 		else
 			enable_idle = 1;
@@ -2002,7 +2169,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
  * Check if new_cfqq should preempt the currently active queue. Return 0 for
  * no or if we aren't sure, a 1 will cause a preempt.
  */
-static int
+static bool
 cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 		   struct request *rq)
 {
@@ -2010,48 +2177,48 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
 
 	cfqq = cfqd->active_queue;
 	if (!cfqq)
-		return 0;
+		return false;
 
 	if (cfq_slice_used(cfqq))
-		return 1;
+		return true;
 
 	if (cfq_class_idle(new_cfqq))
-		return 0;
+		return false;
 
 	if (cfq_class_idle(cfqq))
-		return 1;
+		return true;
 
 	/*
 	 * if the new request is sync, but the currently running queue is
 	 * not, let the sync request have priority.
 	 */
 	if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
-		return 1;
+		return true;
 
 	/*
 	 * So both queues are sync. Let the new request get disk time if
 	 * it's a metadata request and the current queue is doing regular IO.
 	 */
 	if (rq_is_meta(rq) && !cfqq->meta_pending)
-		return 1;
+		return false;
 
 	/*
 	 * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
 	 */
 	if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
-		return 1;
+		return true;
 
 	if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
-		return 0;
+		return false;
 
 	/*
 	 * if this request is as-good as one we would expect from the
 	 * current cfqq, let it preempt
 	 */
-	if (cfq_rq_close(cfqd, rq))
-		return 1;
+	if (cfq_rq_close(cfqd, cfqq, rq))
+		return true;
 
-	return 0;
+	return false;
 }
 
 /*
@@ -2090,10 +2257,10 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 		cfqq->meta_pending++;
 
 	cfq_update_io_thinktime(cfqd, cic);
-	cfq_update_io_seektime(cfqd, cic, rq);
+	cfq_update_io_seektime(cfqd, cfqq, rq);
 	cfq_update_idle_window(cfqd, cfqq, cic);
 
-	cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
+	cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
 
 	if (cfqq == cfqd->active_queue) {
 		/*
@@ -2134,9 +2301,9 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
 	cfq_log_cfqq(cfqd, cfqq, "insert_request");
 	cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
 
-	cfq_add_rq_rb(rq);
-
+	rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
 	list_add_tail(&rq->queuelist, &cfqq->fifo);
+	cfq_add_rq_rb(rq);
 
 	cfq_rq_enqueued(cfqd, cfqq, rq);
 }
@@ -2147,6 +2314,8 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
  */
 static void cfq_update_hw_tag(struct cfq_data *cfqd)
 {
+	struct cfq_queue *cfqq = cfqd->active_queue;
+
 	if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak)
 		cfqd->rq_in_driver_peak = rq_in_driver(cfqd);
 
@@ -2154,6 +2323,16 @@ static void cfq_update_hw_tag(struct cfq_data *cfqd)
 	    rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN)
 		return;
 
+	/*
+	 * If active queue hasn't enough requests and can idle, cfq might not
+	 * dispatch sufficient requests to hardware. Don't zero hw_tag in this
+	 * case
+	 */
+	if (cfqq && cfq_cfqq_idle_window(cfqq) &&
+	    cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] <
+	    CFQ_HW_QUEUE_MIN && rq_in_driver(cfqd) < CFQ_HW_QUEUE_MIN)
+		return;
+
 	if (cfqd->hw_tag_samples++ < 50)
 		return;
 
@@ -2211,13 +2390,13 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 		 */
 		if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
 			cfq_slice_expired(cfqd, 1);
-		else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq, 1) &&
+		else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq) &&
 			 sync && !rq_noidle(rq))
 			cfq_arm_slice_timer(cfqd);
 	}
 
 	if (!rq_in_driver(cfqd))
-		cfq_schedule_dispatch(cfqd, 0);
+		cfq_schedule_dispatch(cfqd);
 }
 
 /*
@@ -2306,6 +2485,43 @@ static void cfq_put_request(struct request *rq)
 	}
 }
 
+static struct cfq_queue *
+cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
+		struct cfq_queue *cfqq)
+{
+	cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
+	cic_set_cfqq(cic, cfqq->new_cfqq, 1);
+	cfq_mark_cfqq_coop(cfqq->new_cfqq);
+	cfq_put_queue(cfqq);
+	return cic_to_cfqq(cic, 1);
+}
+
+static int should_split_cfqq(struct cfq_queue *cfqq)
+{
+	if (cfqq->seeky_start &&
+	    time_after(jiffies, cfqq->seeky_start + CFQQ_COOP_TOUT))
+		return 1;
+	return 0;
+}
+
+/*
+ * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
+ * was the last process referring to said cfqq.
+ */
+static struct cfq_queue *
+split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
+{
+	if (cfqq_process_refs(cfqq) == 1) {
+		cfqq->seeky_start = 0;
+		cfqq->pid = current->pid;
+		cfq_clear_cfqq_coop(cfqq);
+		return cfqq;
+	}
+
+	cic_set_cfqq(cic, NULL, 1);
+	cfq_put_queue(cfqq);
+	return NULL;
+}
 /*
  * Allocate cfq data structures associated with this request.
  */
@@ -2315,7 +2531,7 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
 	struct cfq_data *cfqd = q->elevator->elevator_data;
 	struct cfq_io_context *cic;
 	const int rw = rq_data_dir(rq);
-	const int is_sync = rq_is_sync(rq);
+	const bool is_sync = rq_is_sync(rq);
 	struct cfq_queue *cfqq;
 	unsigned long flags;
 
@@ -2328,10 +2544,30 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
 	if (!cic)
 		goto queue_fail;
 
+new_queue:
 	cfqq = cic_to_cfqq(cic, is_sync);
 	if (!cfqq || cfqq == &cfqd->oom_cfqq) {
 		cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
 		cic_set_cfqq(cic, cfqq, is_sync);
+	} else {
+		/*
+		 * If the queue was seeky for too long, break it apart.
+		 */
+		if (cfq_cfqq_coop(cfqq) && should_split_cfqq(cfqq)) {
+			cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq");
+			cfqq = split_cfqq(cic, cfqq);
+			if (!cfqq)
+				goto new_queue;
+		}
+
+		/*
+		 * Check to see if this queue is scheduled to merge with
+		 * another, closely cooperating queue.  The merging of
+		 * queues happens here as it must be done in process context.
+		 * The reference on new_cfqq was taken in merge_cfqqs.
+		 */
+		if (cfqq->new_cfqq)
+			cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq);
 	}
 
 	cfqq->allocated[rw]++;
@@ -2347,7 +2583,7 @@ queue_fail:
 	if (cic)
 		put_io_context(cic->ioc);
 
-	cfq_schedule_dispatch(cfqd, 0);
+	cfq_schedule_dispatch(cfqd);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 	cfq_log(cfqd, "set_request fail");
 	return 1;
@@ -2356,7 +2592,7 @@ queue_fail:
 static void cfq_kick_queue(struct work_struct *work)
 {
 	struct cfq_data *cfqd =
-		container_of(work, struct cfq_data, unplug_work.work);
+		container_of(work, struct cfq_data, unplug_work);
 	struct request_queue *q = cfqd->queue;
 
 	spin_lock_irq(q->queue_lock);
@@ -2410,7 +2646,7 @@ static void cfq_idle_slice_timer(unsigned long data)
 expire:
 	cfq_slice_expired(cfqd, timed_out);
 out_kick:
-	cfq_schedule_dispatch(cfqd, 0);
+	cfq_schedule_dispatch(cfqd);
 out_cont:
 	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
 }
@@ -2418,7 +2654,7 @@ out_cont:
 static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
 {
 	del_timer_sync(&cfqd->idle_slice_timer);
-	cancel_delayed_work_sync(&cfqd->unplug_work);
+	cancel_work_sync(&cfqd->unplug_work);
 }
 
 static void cfq_put_async_queues(struct cfq_data *cfqd)
@@ -2500,7 +2736,7 @@ static void *cfq_init_queue(struct request_queue *q)
 	cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
 	cfqd->idle_slice_timer.data = (unsigned long) cfqd;
 
-	INIT_DELAYED_WORK(&cfqd->unplug_work, cfq_kick_queue);
+	INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
 
 	cfqd->cfq_quantum = cfq_quantum;
 	cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
@@ -2511,7 +2747,7 @@ static void *cfq_init_queue(struct request_queue *q)
 	cfqd->cfq_slice[1] = cfq_slice_sync;
 	cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
 	cfqd->cfq_slice_idle = cfq_slice_idle;
-	cfqd->cfq_desktop = 1;
+	cfqd->cfq_latency = 1;
 	cfqd->hw_tag = 1;
 	cfqd->last_end_sync_rq = jiffies;
 	return cfqd;
@@ -2581,7 +2817,7 @@ SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
 SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
 SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
 SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
-SHOW_FUNCTION(cfq_desktop_show, cfqd->cfq_desktop, 0);
+SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
@@ -2613,7 +2849,7 @@ STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
 STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
 		UINT_MAX, 0);
-STORE_FUNCTION(cfq_desktop_store, &cfqd->cfq_desktop, 0, 1, 0);
+STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
 #undef STORE_FUNCTION
 
 #define CFQ_ATTR(name) \
@@ -2629,7 +2865,7 @@ static struct elv_fs_entry cfq_attrs[] = {
 	CFQ_ATTR(slice_async),
 	CFQ_ATTR(slice_async_rq),
 	CFQ_ATTR(slice_idle),
-	CFQ_ATTR(desktop),
+	CFQ_ATTR(low_latency),
 	__ATTR_NULL
 };