From e2d845211eda9cf296e8edf6724b3d541f4fbfd5 Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Tue, 29 Jan 2013 10:09:20 +0000 Subject: Btrfs: use percpu counter for dirty metadata count ->dirty_metadata_bytes is accessed very frequently, so use percpu counter instead of the u64 variant to reduce the contention of the lock. This patch also fixed the problem that we access it without lock protection in __btrfs_btree_balance_dirty(), which may cause we skip the dirty pages flush. Signed-off-by: Miao Xie Signed-off-by: Josef Bacik --- fs/btrfs/extent_io.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index bda36fef301..b9019c847c5 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3122,12 +3122,9 @@ static int lock_extent_buffer_for_io(struct extent_buffer *eb, set_bit(EXTENT_BUFFER_WRITEBACK, &eb->bflags); spin_unlock(&eb->refs_lock); btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN); - spin_lock(&fs_info->delalloc_lock); - if (fs_info->dirty_metadata_bytes >= eb->len) - fs_info->dirty_metadata_bytes -= eb->len; - else - WARN_ON(1); - spin_unlock(&fs_info->delalloc_lock); + __percpu_counter_add(&fs_info->dirty_metadata_bytes, + -eb->len, + fs_info->dirty_metadata_batch); ret = 1; } else { spin_unlock(&eb->refs_lock); -- cgit v1.2.3-70-g09d2