From 9f3a074d108810139ad4af49a29d347a4cf41e9a Mon Sep 17 00:00:00 2001 From: Miao Xie Date: Mon, 4 Nov 2013 23:13:24 +0800 Subject: [PATCH] Btrfs: don't wait for all the async delalloc when shrinking delalloc It was very likely that there were lots of async delalloc pages in the filesystem, if we waited until all the pages were flushed, we would be blocked for a long time, and the performance would also drop down. Signed-off-by: Miao Xie Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/extent-tree.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index d8da538d01fb..83bffbea7d97 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4079,9 +4079,19 @@ static void shrink_delalloc(struct btrfs_root *root, u64 to_reclaim, u64 orig, * We need to wait for the async pages to actually start before * we do anything. */ - wait_event(root->fs_info->async_submit_wait, - !atomic_read(&root->fs_info->async_delalloc_pages)); + max_reclaim = atomic_read(&root->fs_info->async_delalloc_pages); + if (!max_reclaim) + goto skip_async; + + if (max_reclaim <= nr_pages) + max_reclaim = 0; + else + max_reclaim -= nr_pages; + wait_event(root->fs_info->async_submit_wait, + atomic_read(&root->fs_info->async_delalloc_pages) <= + (int)max_reclaim); +skip_async: if (!trans) flush = BTRFS_RESERVE_FLUSH_ALL; else -- 2.30.2