diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 1bf210d..1aed1f4 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -429,31 +429,36 @@
 	return 0;
 }
 
+static unsigned long async_submit_limit(struct btrfs_fs_info *info)
+{
+	unsigned long limit = min_t(unsigned long,
+				    info->workers.max_workers,
+				    info->fs_devices->open_devices);
+	return 256 * limit;
+}
+
 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 {
-	int limit = 256 * info->fs_devices->open_devices;
-
-	if (iodone)
-		limit = (limit * 3) / 2;
-	if (atomic_read(&info->nr_async_submits) > limit)
-		return 1;
-
-	return atomic_read(&info->nr_async_bios) > limit;
+	return atomic_read(&info->nr_async_bios) > async_submit_limit(info);
 }
 
 static void run_one_async_submit(struct btrfs_work *work)
 {
 	struct btrfs_fs_info *fs_info;
 	struct async_submit_bio *async;
+	int limit;
 
 	async = container_of(work, struct  async_submit_bio, work);
 	fs_info = BTRFS_I(async->inode)->root->fs_info;
+
+	limit = async_submit_limit(fs_info);
+	limit = limit * 2 / 3;
+
 	atomic_dec(&fs_info->nr_async_submits);
 
-	if ((async->bio->bi_rw & (1 << BIO_RW)) &&
-	    !btrfs_congested_async(fs_info, 1)) {
-		clear_bdi_congested(&fs_info->bdi, WRITE);
-	}
+	if (atomic_read(&fs_info->nr_async_submits) < limit)
+		wake_up(&fs_info->async_submit_wait);
+
 	async->submit_bio_hook(async->inode, async->rw, async->bio,
 			       async->mirror_num);
 	kfree(async);
@@ -464,6 +469,7 @@
 			extent_submit_bio_hook_t *submit_bio_hook)
 {
 	struct async_submit_bio *async;
+	int limit = async_submit_limit(fs_info);
 
 	async = kmalloc(sizeof(*async), GFP_NOFS);
 	if (!async)
@@ -478,6 +484,10 @@
 	async->work.flags = 0;
 	atomic_inc(&fs_info->nr_async_submits);
 	btrfs_queue_worker(&fs_info->workers, &async->work);
+
+	wait_event_timeout(fs_info->async_submit_wait,
+			   (atomic_read(&fs_info->nr_async_submits) < limit),
+			   HZ/10);
 	return 0;
 }
 
@@ -545,16 +555,11 @@
 	if (wbc->sync_mode == WB_SYNC_NONE) {
 		u64 num_dirty;
 		u64 start = 0;
-		unsigned long thresh = 96 * 1024 * 1024;
+		unsigned long thresh = 8 * 1024 * 1024;
 
 		if (wbc->for_kupdate)
 			return 0;
 
-		if (current_is_pdflush()) {
-			thresh = 96 * 1024 * 1024;
-		} else {
-			thresh = 8 * 1024 * 1024;
-		}
 		num_dirty = count_range_bits(tree, &start, (u64)-1,
 					     thresh, EXTENT_DIRTY);
 		if (num_dirty < thresh) {
@@ -1333,6 +1338,7 @@
 	mutex_init(&fs_info->volume_mutex);
 	init_waitqueue_head(&fs_info->transaction_throttle);
 	init_waitqueue_head(&fs_info->transaction_wait);
+	init_waitqueue_head(&fs_info->async_submit_wait);
 
 #if 0
 	ret = add_hasher(fs_info, "crc32c");
@@ -1380,6 +1386,7 @@
 	 * devices
 	 */
 	fs_info->submit_workers.idle_thresh = 64;
+	fs_info->workers.idle_thresh = 32;
 
 	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1);
 	btrfs_init_workers(&fs_info->endio_workers, "endio",
@@ -1849,7 +1856,7 @@
 	struct extent_io_tree *tree;
 	u64 num_dirty;
 	u64 start = 0;
-	unsigned long thresh = 2 * 1024 * 1024;
+	unsigned long thresh = 12 * 1024 * 1024;
 	tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 
 	if (current_is_pdflush())