diff -urNp --exclude CVS --exclude BitKeeper x-ref/drivers/block/elevator.c x/drivers/block/elevator.c
--- x-ref/drivers/block/elevator.c	2003-07-17 06:01:25.000000000 +0200
+++ x/drivers/block/elevator.c	2003-07-17 06:02:25.000000000 +0200
@@ -74,6 +74,30 @@ inline int bh_rq_in_between(struct buffe
 	return 0;
 }
 
+static int rq_mergeable(struct request *req, struct buffer_head *bh,
+			request_queue_t *q, int rw, int count, int max_sectors)
+{
+	if (q->head_active && !q->plugged) {
+		struct request *next;
+		next = blkdev_entry_next_request(&q->queue_head);
+		if (next == req)
+			return 0;
+	}
+	if (q->head_active)
+		return 0;
+	if (req->waiting)
+		return 0;
+	if (req->rq_dev != bh->b_rdev)
+		return 0;
+	if (req->cmd != rw)
+		return 0;
+	if (req->nr_sectors + count > max_sectors)
+		return 0;
+	if (bh_elv_seq(bh) != bh_elv_seq(req->bh))
+		return 0;
+
+	return 1;
+}
 
 int elevator_linus_merge(request_queue_t *q, struct request **req,
 			 struct list_head * head,
@@ -91,6 +115,25 @@ int elevator_linus_merge(request_queue_t
 		entry = &q->atomic_head;
 	real_head = entry;
 
+	/*
+	 * check last merge hint
+	 */
+	if (q->last_merge) {
+		__rq = q->last_merge;
+
+		if (rq_mergeable(__rq, bh, q, rw, count, max_sectors)) {
+			if (__rq->sector + __rq->nr_sectors == bh->b_rsector) {
+				*req = __rq;
+				ret = ELEVATOR_BACK_MERGE;
+				goto out;
+			} else if (__rq->sector - count == bh->b_rsector) {
+				*req = __rq;
+				ret = ELEVATOR_FRONT_MERGE;
+				goto out;
+			}
+		}
+	}
+
 	while (!backmerge_only && (entry = entry->prev) != head) {
 		__rq = blkdev_entry_to_request(entry);
 
@@ -118,15 +161,18 @@ int elevator_linus_merge(request_queue_t
 		if (__rq->sector + __rq->nr_sectors == bh->b_rsector) {
 			ret = ELEVATOR_BACK_MERGE;
 			*req = __rq;
+			q->last_merge = __rq;
 			break;
 		} else if (__rq->sector - count == bh->b_rsector && !backmerge_only) {
 			ret = ELEVATOR_FRONT_MERGE;
 			__rq->elevator_sequence--;
 			*req = __rq;
+			q->last_merge = __rq;
 			break;
 		}
 	}
 
+out:
 	/*
 	 * account merge (ret != 0, cost is 1) or seeky insert (*req is set,
 	 * cost is ELV_LINUS_SEEK_COST
@@ -148,6 +194,8 @@ void elevator_linus_merge_req(struct req
 {
 	if (next->elevator_sequence < req->elevator_sequence)
 		req->elevator_sequence = next->elevator_sequence;
+	if (req->q)
+		req->q->last_merge = req;
 }
 
 /*
diff -urNp --exclude CVS --exclude BitKeeper x-ref/drivers/block/ll_rw_blk.c x/drivers/block/ll_rw_blk.c
--- x-ref/drivers/block/ll_rw_blk.c	2003-07-17 06:01:25.000000000 +0200
+++ x/drivers/block/ll_rw_blk.c	2003-07-17 06:01:35.000000000 +0200
@@ -440,10 +440,18 @@ static void generic_plug_device(request_
  */
 static inline void __generic_unplug_device(request_queue_t *q)
 {
+	struct request *next;
+
 	if (q->plugged) {
 		q->plugged = 0;
-		if (!list_empty(&q->queue_head))
+		if (!list_empty(&q->queue_head)) {
+			next = blkdev_entry_next_request(&q->queue_head);
+
+			if (next == q->last_merge)
+				q->last_merge = NULL;
+
 			q->request_fn(q);
+		}
 	}
 }
 
@@ -677,6 +685,7 @@ void blk_init_queue(request_queue_t * q,
 	q->plug_tq.data		= q;
 	q->plugged        	= 0;
 	q->can_throttle		= 0;
+	q->last_merge		= NULL;
 
 	/*
 	 * These booleans describe the queue properties.  We set the
@@ -992,6 +1001,9 @@ static inline void add_request(request_q
 	 * inserted at elevator_merge time
 	 */
 	list_add(&req->queue, insert_here);
+
+	if (!q->last_merge)
+		q->last_merge = req;
 }
 
 /*
diff -urNp --exclude CVS --exclude BitKeeper x-ref/include/linux/blk.h x/include/linux/blk.h
--- x-ref/include/linux/blk.h	2003-07-17 06:01:20.000000000 +0200
+++ x/include/linux/blk.h	2003-07-17 06:01:27.000000000 +0200
@@ -86,6 +86,13 @@ void initrd_init(void);
 
 static inline void blkdev_dequeue_request(struct request * req)
 {
+	request_queue_t *q = req->q;
+
+	if (q) {
+		if (q->last_merge == req || (q->head_active && q->last_merge == blkdev_next_request(req)))
+			q->last_merge = NULL;
+	}
+
 	list_del(&req->queue);
 }
 
diff -urNp --exclude CVS --exclude BitKeeper x-ref/include/linux/blkdev.h x/include/linux/blkdev.h
--- x-ref/include/linux/blkdev.h	2003-07-17 06:01:25.000000000 +0200
+++ x/include/linux/blkdev.h	2003-07-17 06:01:27.000000000 +0200
@@ -107,6 +107,7 @@ struct request_queue
 	struct list_head	queue_head;
 	struct list_head	atomic_head;
 	elevator_t		elevator;
+	struct request		*last_merge;
 
 	request_fn_proc		* request_fn;
 	merge_request_fn	* back_merge_fn;