From c6adc9cc082e3cffda153999c9b9f8a8baaaaf45 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Tue, 28 May 2013 10:05:39 +0000 Subject: Btrfs: merge pending IO for tree log write back Before applying this patch, we flushed the log tree of the fs/file tree firstly, and then flushed the log root tree. It is ineffective, especially on the hard disk. This patch improved this problem by wrapping the above two flushes by the same blk_plug. By test, the performance of the sync write went up ~60%(2.9MB/s -> 4.6MB/s) on my scsi disk whose disk buffer was enabled. Test step: # mkfs.btrfs -f -m single # mount # dd if=/dev/zero of=/file0 bs=32K count=1024 oflag=sync Signed-off-by: Miao Xie Signed-off-by: Josef Bacik --- fs/btrfs/transaction.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/transaction.c') diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index eec8686416ca..8c8b80085e75 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -778,9 +778,7 @@ int btrfs_write_marked_extents(struct btrfs_root *root, struct extent_state *cached_state = NULL; u64 start = 0; u64 end; - struct blk_plug plug; - blk_start_plug(&plug); while (!find_first_extent_bit(dirty_pages, start, &start, &end, mark, &cached_state)) { convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, @@ -794,7 +792,6 @@ int btrfs_write_marked_extents(struct btrfs_root *root, } if (err) werr = err; - blk_finish_plug(&plug); return werr; } @@ -839,8 +836,11 @@ int btrfs_write_and_wait_marked_extents(struct btrfs_root *root, { int ret; int ret2; + struct blk_plug plug; + blk_start_plug(&plug); ret = btrfs_write_marked_extents(root, dirty_pages, mark); + blk_finish_plug(&plug); ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark); if (ret) -- cgit v1.2.3