block/deadline-iosched.c |   55 ++++++++++++++++++++++++-----------------------
 1 files changed, 29 insertions(+), 26 deletions(-)

diff -puN drivers/block/deadline-iosched.c~deadline-np-43 drivers/block/deadline-iosched.c
--- 25/drivers/block/deadline-iosched.c~deadline-np-43	2003-01-28 21:35:14.000000000 -0800
+++ 25-akpm/drivers/block/deadline-iosched.c	2003-01-28 21:35:14.000000000 -0800
@@ -24,9 +24,9 @@
  */
 static int read_expire = HZ / 2;  /* max time before a read is submitted. */
 static int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
+static int batch_expire = HZ / 4; /* Interval between recalculation of
+				     writes_starved */
 static int writes_starved = 2;    /* max times reads can starve a write */
-static int fifo_batch = 16;       /* # of sequential requests treated as one
-				     by the above parameters. For throughput. */
 
 static const int deadline_hash_shift = 10;
 #define DL_HASH_BLOCK(sec)	((sec) >> 3)
@@ -58,7 +58,7 @@ struct deadline_data {
 	struct list_head *dispatch;	/* driver dispatch queue */
 	struct list_head *hash;		/* request hash */
 	unsigned long hash_valid_count;	/* barrier hash count */
-	unsigned int batching;		/* number of sequential requests made */
+	unsigned int batch_expires;	/* time until this batch expires */
 	int batch_data_dir;		/* current/last batch READ or WRITE */
 	unsigned int starved;		/* times reads have starved writes */
 
@@ -66,7 +66,7 @@ struct deadline_data {
 	 * settings that change how the i/o scheduler behaves
 	 */
 	int fifo_expire[2];
-	int fifo_batch;
+	int batch_expire;
 	int writes_starved;
 	int front_merges;
 };
@@ -497,8 +497,20 @@ static inline int deadline_check_fifo(st
 }
 
 /*
+ * deadline_check_batch returns 0 if the current batch has not expired,
+ * 1 otherwise.
+ */
+static inline int deadline_check_batch(struct deadline_data *dd)
+{
+	if (time_after(jiffies, dd->batch_expires))
+		return 1;
+
+	return 0;
+}
+
+/*
  * deadline_dispatch_requests selects the best request according to
- * read/write expire, fifo_batch, etc
+ * read/write expire, batch expire, etc
  */
 static int deadline_dispatch_requests(struct deadline_data *dd)
 {
@@ -512,24 +524,16 @@ static int deadline_dispatch_requests(st
 	 */
 	drq = dd->next_drq[dd->batch_data_dir];
 
-	if (drq) {
-		/* we have a "next request" */
-		
-		if (dd->last_sector[dd->batch_data_dir] != drq->request->sector)
-			/* end the batch on a non sequential request */
-			dd->batching += dd->fifo_batch;
-		
-		if (dd->batching < dd->fifo_batch)
-			/* we are still entitled to batch */
-			goto dispatch_request;
-	}
+	if (drq && !deadline_check_batch(dd))
+		/* we have a "next request" and our batch is still running */
+		goto dispatch_request;
 
 	/*
 	 * at this point we are not running a batch. select the appropriate
 	 * data direction (read / write)
 	 */
 	
-	dd->batching = 0; /* start a new batch */
+	dd->batch_expires = jiffies + dd->batch_expire; /* start a new batch */
 
 	if (reads) {
 		BUG_ON(RB_EMPTY(&dd->sort_list[READ]));
@@ -577,7 +581,6 @@ dispatch_request:
 	/*
 	 * drq is the selected appropriate request.
 	 */
-	dd->batching++;
 	deadline_move_request(dd, drq);
 
 	return 1;
@@ -736,7 +739,7 @@ static int deadline_init(request_queue_t
 	dd->hash_valid_count = 1;
 	dd->writes_starved = writes_starved;
 	dd->front_merges = 1;
-	dd->fifo_batch = fifo_batch;
+	dd->batch_expire = batch_expire;
 	e->elevator_data = dd;
 
 	for (i = READ; i <= WRITE; i++) {
@@ -800,7 +803,7 @@ SHOW_FUNCTION(deadline_readexpire_show, 
 SHOW_FUNCTION(deadline_writeexpire_show, dd->fifo_expire[WRITE]);
 SHOW_FUNCTION(deadline_writesstarved_show, dd->writes_starved);
 SHOW_FUNCTION(deadline_frontmerges_show, dd->front_merges);
-SHOW_FUNCTION(deadline_fifobatch_show, dd->fifo_batch);
+SHOW_FUNCTION(deadline_batchexpire_show, dd->batch_expire);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX)				\
@@ -817,7 +820,7 @@ STORE_FUNCTION(deadline_readexpire_store
 STORE_FUNCTION(deadline_writeexpire_store, &dd->fifo_expire[WRITE], 0, INT_MAX);
 STORE_FUNCTION(deadline_writesstarved_store, &dd->writes_starved, INT_MIN, INT_MAX);
 STORE_FUNCTION(deadline_frontmerges_store, &dd->front_merges, 0, 1);
-STORE_FUNCTION(deadline_fifobatch_store, &dd->fifo_batch, 0, INT_MAX);
+STORE_FUNCTION(deadline_batchexpire_store, &dd->batch_expire, 0, INT_MAX);
 #undef STORE_FUNCTION
 
 static struct deadline_fs_entry deadline_readexpire_entry = {
@@ -840,10 +843,10 @@ static struct deadline_fs_entry deadline
 	.show = deadline_frontmerges_show,
 	.store = deadline_frontmerges_store,
 };
-static struct deadline_fs_entry deadline_fifobatch_entry = {
-	.attr = {.name = "fifo_batch", .mode = S_IRUGO | S_IWUSR },
-	.show = deadline_fifobatch_show,
-	.store = deadline_fifobatch_store,
+static struct deadline_fs_entry deadline_batchexpire_entry = {
+	.attr = {.name = "batch_expire", .mode = S_IRUGO | S_IWUSR },
+	.show = deadline_batchexpire_show,
+	.store = deadline_batchexpire_store,
 };
 
 static struct attribute *default_attrs[] = {
@@ -851,7 +854,7 @@ static struct attribute *default_attrs[]
 	&deadline_writeexpire_entry.attr,
 	&deadline_writesstarved_entry.attr,
 	&deadline_frontmerges_entry.attr,
-	&deadline_fifobatch_entry.attr,
+	&deadline_batchexpire_entry.attr,
 	NULL,
 };
 

_