[PATCH] raid5:Only move IO_THRESHOLD stripes from delay_list to hold_list in raid5_activate_delayed().

[majianpeng <majianpeng@gmail.com>]

To imporve write performance and as posssible as to achieve full-write,
it only fetch IO_THRESHOLD stripes from delay_list to hold_list.

Signed-off-by: majianpeng <majianpeng@gmail.com>
---
 drivers/md/raid5.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 04348d7..45308c5 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -3662,6 +3662,7 @@ finish:
 
 static void raid5_activate_delayed(struct r5conf *conf)
 {
+	int count = 0;
 	if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD) {
 		while (!list_empty(&conf->delayed_list)) {
 			struct list_head *l = conf->delayed_list.next;
@@ -3672,6 +3673,8 @@ static void raid5_activate_delayed(struct r5conf *conf)
 			if (!test_and_set_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
 				atomic_inc(&conf->preread_active_stripes);
 			list_add_tail(&sh->lru, &conf->hold_list);
+			if (count++ >= IO_THRESHOLD)
+				break;
 		}
 	}
 }
-- 
1.7.5.4