---

yaml
---
r: 258607
b: refs/heads/master
c: 55c022b
h: refs/heads/master
i:
  258605: 521ffeb
  258603: d0f36e6
  258599: 3534dd6
  258591: b7775b1
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 719c0c590609809365c6f3da2f923cd84dc99113
+refs/heads/master: 55c022bbddb2c056b5dff1bd1b1758d31b6d64c9

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);

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 *);