Btrfs: set leave_spinning in btrfs_get_extent (e49aabd9) · Commits · 戴 / test

Unless it's going to read inline extents from btree leaf to page, btrfs_get_extent won't sleep during the period of holding path lock. This sets leave_spinning at first and sets path to blocking mode right before reading inline extent if that's the case. The benefit is that a path in spinning mode typically has lower impact (faster) on waiters rather than that in the blocking mode. Signed-off-by:

Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by:

David Sterba <dsterba@suse.com> Signed-off-by:

David Sterba <dsterba@suse.com>

fs/btrfs/inode.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -6827,6 +6827,12 @@ struct extent_map btrfs_get_extent(struct btrfs_inode inode,
		/* Chances are we'll be called again, so go ahead and do readahead */
		path->reada = READA_FORWARD;

		/*
		* Unless we're going to uncompress the inline extent, no sleep would
		* happen.
		*/
		path->leave_spinning = 1;

		ret = btrfs_lookup_file_extent(NULL, root, path, objectid, start, 0);
		if (ret < 0) {
		err = ret;
		@@ -6929,6 +6935,8 @@ next:
		em->orig_block_len = em->len;
		em->orig_start = em->start;
		ptr = btrfs_file_extent_inline_start(item) + extent_offset;

		btrfs_set_path_blocking(path);
		if (!PageUptodate(page)) {
		if (btrfs_file_extent_compression(leaf, item) !=
		BTRFS_COMPRESS_NONE) {

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