From: Miao Xie Date: Mon, 4 Nov 2013 15:13:24 +0000 (+0800) Subject: Btrfs: don't wait for all the async delalloc when shrinking delalloc X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=9f3a074d108810139ad4af49a29d347a4cf41e9a;p=deliverable%2Flinux.git 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 --- 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