From e06b1acde30136a8c2cc3b114b539290ef494748 Mon Sep 17 00:00:00 2001
From: Shaohua Li <shaohua.li@intel.com>
Date: Fri, 8 Jul 2011 08:19:20 +0200
Subject: [PATCH] --- yaml --- r: 258607 b: refs/heads/master c:
 55c022bbddb2c056b5dff1bd1b1758d31b6d64c9 h: refs/heads/master i:   258605:
 521ffeb0e9c679ab68fb9fb06fcfc9e666f16ae6   258603:
 d0f36e69f39947e7718e89865af00b2caf64e0cd   258599:
 3534dd6f43b9d44877d60ef0074223b786620263   258591:
 b7775b175dd7c519fd67271ea03d3a3df83933ee v: v3

---
 [refs]                       | 2 +-
 trunk/block/blk-core.c       | 5 +++++
 trunk/include/linux/blkdev.h | 3 +++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index b4e23a1d02b9..702a49954eb5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 719c0c590609809365c6f3da2f923cd84dc99113
+refs/heads/master: 55c022bbddb2c056b5dff1bd1b1758d31b6d64c9
diff --git a/trunk/block/blk-core.c b/trunk/block/blk-core.c
index d2f8f4049abd..a56485292062 100644
--- a/trunk/block/blk-core.c
+++ b/trunk/block/blk-core.c
@@ -1302,7 +1302,10 @@ static int __make_request(struct request_queue *q, struct bio *bio)
 				plug->should_sort = 1;
 		}
 		list_add_tail(&req->queuelist, &plug->list);
+		plug->count++;
 		drive_stat_acct(req, 1);
+		if (plug->count >= BLK_MAX_REQUEST_COUNT)
+			blk_flush_plug_list(plug, false);
 	} else {
 		spin_lock_irq(q->queue_lock);
 		add_acct_request(q, req, where);
@@ -2626,6 +2629,7 @@ void blk_start_plug(struct blk_plug *plug)
 	INIT_LIST_HEAD(&plug->list);
 	INIT_LIST_HEAD(&plug->cb_list);
 	plug->should_sort = 0;
+	plug->count = 0;
 
 	/*
 	 * If this is a nested plug, don't actually assign it. It will be
@@ -2709,6 +2713,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
 		return;
 
 	list_splice_init(&plug->list, &list);
+	plug->count = 0;
 
 	if (plug->should_sort) {
 		list_sort(NULL, &list, plug_rq_cmp);
diff --git a/trunk/include/linux/blkdev.h b/trunk/include/linux/blkdev.h
index 36f2e2b99ae3..92edb9601242 100644
--- a/trunk/include/linux/blkdev.h
+++ b/trunk/include/linux/blkdev.h
@@ -862,7 +862,10 @@ struct blk_plug {
 	struct list_head list;
 	struct list_head cb_list;
 	unsigned int should_sort;
+	unsigned int count;
 };
+#define BLK_MAX_REQUEST_COUNT 16
+
 struct blk_plug_cb {
 	struct list_head list;
 	void (*callback)(struct blk_plug_cb *);