diff -ruN -X linux-2.6.20.2/Documentation/dontdiff linux-2.6.20.2/drivers/md/raid5.c linux-2.6.20.2-raid/drivers/md/raid5.c
--- linux-2.6.20.2/drivers/md/raid5.c	2007-03-09 20:58:04.000000000 +0200
+++ linux-2.6.20.2-raid/drivers/md/raid5.c	2007-03-30 12:37:55.000000000 +0300
@@ -65,6 +65,7 @@
 #define NR_HASH			(PAGE_SIZE / sizeof(struct hlist_head))
 #define HASH_MASK		(NR_HASH - 1)
 
+
 #define stripe_hash(conf, sect)	(&((conf)->stripe_hashtbl[((sect) >> STRIPE_SHIFT) & HASH_MASK]))
 
 /* bio's attached to a stripe+device for I/O are linked together in bi_sector
@@ -234,6 +235,8 @@
 	sh->sector = sector;
 	sh->pd_idx = pd_idx;
 	sh->state = 0;
+	sh->active_preread_jiffies =
+        		msecs_to_jiffies( atomic_read(&conf->deadline_ms) )+ jiffies;
 
 	sh->disks = disks;
 
@@ -628,6 +631,7 @@
 	
 	clear_bit(R5_LOCKED, &sh->dev[i].flags);
 	set_bit(STRIPE_HANDLE, &sh->state);
+	sh->active_preread_jiffies = jiffies;
 	release_stripe(sh);
 	return 0;
 }
@@ -1255,8 +1259,11 @@
 		bip = &sh->dev[dd_idx].towrite;
 		if (*bip == NULL && sh->dev[dd_idx].written == NULL)
 			firstwrite = 1;
-	} else
+	} else{
 		bip = &sh->dev[dd_idx].toread;
+		sh->active_preread_jiffies = jiffies;	
+	}
+
 	while (*bip && (*bip)->bi_sector < bi->bi_sector) {
 		if ((*bip)->bi_sector + ((*bip)->bi_size >> 9) > bi->bi_sector)
 			goto overlap;
@@ -2437,13 +2444,27 @@
 
 
 
-static void raid5_activate_delayed(raid5_conf_t *conf)
+static struct stripe_head*  raid5_activate_delayed(raid5_conf_t *conf)
 {
 	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
 		while (!list_empty(&conf->delayed_list)) {
 			struct list_head *l = conf->delayed_list.next;
 			struct stripe_head *sh;
 			sh = list_entry(l, struct stripe_head, lru);
+      			
+			if( time_before(jiffies,sh->active_preread_jiffies) ){
+        		  PRINTK("deadline : no expire sec=%lld %8u %8u\n",
+	               		(unsigned long long) sh->sector,
+               			jiffies_to_msecs(sh->active_preread_jiffies),
+               			jiffies_to_msecs(jiffies));
+        		  return sh;
+      			}
+      			else{
+			      PRINTK("deadline:  expire:sec=%lld %8u %8u\n",
+	               			(unsigned long long)sh->sector,
+        	       			jiffies_to_msecs(sh->active_preread_jiffies),
+               				jiffies_to_msecs(jiffies));
+			}
 			list_del_init(l);
 			clear_bit(STRIPE_DELAYED, &sh->state);
 			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
@@ -2451,6 +2472,7 @@
 			list_add_tail(&sh->lru, &conf->handle_list);
 		}
 	}
+     return NULL;
 }
 
 static void activate_bit_delay(raid5_conf_t *conf)
@@ -3191,7 +3213,7 @@
  */
 static void raid5d (mddev_t *mddev)
 {
-	struct stripe_head *sh;
+	struct stripe_head *sh,*delayed_sh=NULL;
 	raid5_conf_t *conf = mddev_to_conf(mddev);
 	int handled;
 
@@ -3218,8 +3240,10 @@
 		    atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD &&
 		    !blk_queue_plugged(mddev->queue) &&
 		    !list_empty(&conf->delayed_list))
-			raid5_activate_delayed(conf);
-
+			delayed_sh=raid5_activate_delayed(conf);
+		
+		if(delayed_sh) break;
+		    
 		while ((bio = remove_bio_from_retry(conf))) {
 			int ok;
 			spin_unlock_irq(&conf->device_lock);
@@ -3254,9 +3278,51 @@
 	unplug_slaves(mddev);
 
 	PRINTK("--- raid5d inactive\n");
+ 	if (delayed_sh){
+   		long wakeup=delayed_sh->active_preread_jiffies-jiffies;
+   		PRINTK("--- raid5d inactive sleep for %d\n",
+            		jiffies_to_msecs(wakeup) );
+   		if (wakeup>0)
+     		mddev->thread->timeout = wakeup;
+  	}
+}
+
+static ssize_t
+raid5_show_stripe_deadline(mddev_t *mddev, char *page)
+{
+  raid5_conf_t *conf = mddev_to_conf(mddev);
+  if (conf)
+    return sprintf(page, "%d\n", atomic_read(&conf->deadline_ms));
+  else
+    return 0;
 }
 
 static ssize_t
+raid5_store_stripe_deadline(mddev_t *mddev, const char *page, size_t len)
+{
+  raid5_conf_t *conf = mddev_to_conf(mddev);
+  char *end;
+  int new;
+  if (len >= PAGE_SIZE)
+    return -EINVAL;
+  if (!conf)
+    return -ENODEV;
+  new = simple_strtoul(page, &end, 10);
+  if (!*page || (*end && *end != '\n') )
+    return -EINVAL;
+  if (new < 0 || new > 10000)
+    return -EINVAL;
+  atomic_set(&conf->deadline_ms,new);
+  return len;
+}
+
+static struct md_sysfs_entry
+raid5_stripe_deadline = __ATTR(stripe_deadline, S_IRUGO | S_IWUSR,
+                                raid5_show_stripe_deadline,
+                               raid5_store_stripe_deadline);
+
+
+static ssize_t
 raid5_show_stripe_cache_size(mddev_t *mddev, char *page)
 {
 	raid5_conf_t *conf = mddev_to_conf(mddev);
@@ -3297,6 +3363,9 @@
 	return len;
 }
 
+
+
+
 static struct md_sysfs_entry
 raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR,
 				raid5_show_stripe_cache_size,
@@ -3318,8 +3387,10 @@
 static struct attribute *raid5_attrs[] =  {
 	&raid5_stripecache_size.attr,
 	&raid5_stripecache_active.attr,
+    &raid5_stripe_deadline.attr,
 	NULL,
 };
+
 static struct attribute_group raid5_attrs_group = {
 	.name = NULL,
 	.attrs = raid5_attrs,
@@ -3567,6 +3638,8 @@
 
 	blk_queue_merge_bvec(mddev->queue, raid5_mergeable_bvec);
 
+	atomic_set(&conf->deadline_ms,0);
+
 	return 0;
 abort:
 	if (conf) {