block/blk-core.c    |    1 +
 block/blk.h         |    8 +++++++-
 block/cfq-iosched.c |   11 ++++++++---
 3 files changed, 16 insertions(+), 4 deletions(-)

Index: linux-2.6/block/cfq-iosched.c
===================================================================
--- linux-2.6.orig/block/cfq-iosched.c	2011-02-22 13:23:25.000000000 -0500
+++ linux-2.6/block/cfq-iosched.c	2011-02-23 11:54:49.488446104 -0500
@@ -498,7 +498,7 @@ static inline bool cfq_bio_sync(struct b
 static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
 {
 	if (cfqd->busy_queues) {
-		cfq_log(cfqd, "schedule dispatch");
+		cfq_log(cfqd, "schedule dispatch: busy_queues=%d rq_queued=%d rq_in_driver=%d q=%p", cfqd->busy_queues, cfqd->rq_queued, cfqd->rq_in_driver, cfqd->queue);
 		kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
 	}
 }
@@ -2229,6 +2229,8 @@ static struct cfq_queue *cfq_select_queu
 {
 	struct cfq_queue *cfqq, *new_cfqq = NULL;
 
+	cfq_log(cfqd, "select_queue: busy_queues=%d rq_queued=%d rq_in_driver=%d", cfqd->busy_queues, cfqd->rq_queued, cfqd->rq_in_driver);
+
 	cfqq = cfqd->active_queue;
 	if (!cfqq)
 		goto new_queue;
@@ -2499,8 +2501,10 @@ static int cfq_dispatch_requests(struct 
 		return cfq_forced_dispatch(cfqd);
 
 	cfqq = cfq_select_queue(cfqd);
-	if (!cfqq)
+	if (!cfqq) {
+		cfq_log(cfqd, "select: no cfqq selected");
 		return 0;
+	}
 
 	/*
 	 * Dispatch a request from this cfqq, if it is allowed
@@ -3359,7 +3363,7 @@ static void cfq_insert_request(struct re
 	struct cfq_data *cfqd = q->elevator->elevator_data;
 	struct cfq_queue *cfqq = RQ_CFQQ(rq);
 
-	cfq_log_cfqq(cfqd, cfqq, "insert_request");
+	cfq_log_cfqq(cfqd, cfqq, "insert_request: busy_queues=%d rq_queued=%d rq_in_driver=%d", cfqd->busy_queues, cfqd->rq_queued, cfqd->rq_in_driver);
 	cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
 
 	rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
@@ -3707,6 +3711,7 @@ static void cfq_kick_queue(struct work_s
 	struct request_queue *q = cfqd->queue;
 
 	spin_lock_irq(q->queue_lock);
+	cfq_log(cfqd, "cfq_kick_queue called. busy_queues=%d rq_queued=%d rq_in_driver=%d", cfqd->busy_queues, cfqd->rq_queued, cfqd->rq_in_driver);
 	__blk_run_queue(cfqd->queue);
 	spin_unlock_irq(q->queue_lock);
 }
Index: linux-2.6/block/blk-core.c
===================================================================
--- linux-2.6.orig/block/blk-core.c	2011-02-22 13:23:25.000000000 -0500
+++ linux-2.6/block/blk-core.c	2011-02-23 11:50:34.406700216 -0500
@@ -413,6 +413,7 @@ void __blk_run_queue(struct request_queu
 		queue_flag_clear(QUEUE_FLAG_REENTER, q);
 	} else {
 		queue_flag_set(QUEUE_FLAG_PLUGGED, q);
+		trace_printk("not recursing. Scheduling another dispatch\n");
 		kblockd_schedule_work(q, &q->unplug_work);
 	}
 }
Index: linux-2.6/block/blk.h
===================================================================
--- linux-2.6.orig/block/blk.h	2011-02-18 13:39:47.000000000 -0500
+++ linux-2.6/block/blk.h	2011-02-23 11:53:37.844304978 -0500
@@ -57,6 +57,8 @@ static inline struct request *__elv_next
 {
 	struct request *rq;
 
+	trace_printk("elv_next_request called. q=%p\n", q);
+
 	while (1) {
 		while (!list_empty(&q->queue_head)) {
 			rq = list_entry_rq(q->queue_head.next);
@@ -68,8 +70,12 @@ static inline struct request *__elv_next
 				return rq;
 		}
 
-		if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
+		trace_printk("No requests in q->queue_head. Will call elevator. q=%p\n", q);
+
+		if (!q->elevator->ops->elevator_dispatch_fn(q, 0)) {
+			trace_printk("No requests in elevator either q=%p\n", q);
 			return NULL;
+		}
 	}
 }