From 0b08851fdaa5f9f74357345d7be44ea584665d5f Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Mon, 17 Jun 2013 14:23:02 -0400 Subject: [PATCH] Btrfs: optimize reada_for_balance This patch does two things. First we no longer explicitly read in the blocks we're trying to readahead. For things like balance_level we may never actually use the blocks so this just adds uneeded latency, and balance_level and split_node will both read in the blocks they care about explicitly so if the blocks need to be waited on it will be done there. Secondly we no longer drop the path if we do readahead, we just set the path blocking before we call reada_for_balance() and then we're good to go. Hopefully this will cut down on the number of re-searches. Thanks, Signed-off-by: Josef Bacik --- fs/btrfs/ctree.c | 46 +++++++++------------------------------------- 1 file changed, 9 insertions(+), 37 deletions(-) diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index c85cde761248..c32d03dff4fc 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2178,12 +2178,8 @@ static void reada_for_search(struct btrfs_root *root, } } -/* - * returns -EAGAIN if it had to drop the path, or zero if everything was in - * cache - */ -static noinline int reada_for_balance(struct btrfs_root *root, - struct btrfs_path *path, int level) +static noinline void reada_for_balance(struct btrfs_root *root, + struct btrfs_path *path, int level) { int slot; int nritems; @@ -2192,12 +2188,11 @@ static noinline int reada_for_balance(struct btrfs_root *root, u64 gen; u64 block1 = 0; u64 block2 = 0; - int ret = 0; int blocksize; parent = path->nodes[level + 1]; if (!parent) - return 0; + return; nritems = btrfs_header_nritems(parent); slot = path->slots[level + 1]; @@ -2224,28 +2219,11 @@ static noinline int reada_for_balance(struct btrfs_root *root, block2 = 0; free_extent_buffer(eb); } - if (block1 || block2) { - ret = -EAGAIN; - - /* release the whole path */ - btrfs_release_path(path); - /* read the blocks */ - if (block1) - readahead_tree_block(root, block1, blocksize, 0); - if (block2) - readahead_tree_block(root, block2, blocksize, 0); - - if (block1) { - eb = read_tree_block(root, block1, blocksize, 0); - free_extent_buffer(eb); - } - if (block2) { - eb = read_tree_block(root, block2, blocksize, 0); - free_extent_buffer(eb); - } - } - return ret; + if (block1) + readahead_tree_block(root, block1, blocksize, 0); + if (block2) + readahead_tree_block(root, block2, blocksize, 0); } @@ -2441,11 +2419,8 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans, goto again; } - sret = reada_for_balance(root, p, level); - if (sret) - goto again; - btrfs_set_path_blocking(p); + reada_for_balance(root, p, level); sret = split_node(trans, root, p, level); btrfs_clear_path_blocking(p, NULL, 0); @@ -2465,11 +2440,8 @@ setup_nodes_for_search(struct btrfs_trans_handle *trans, goto again; } - sret = reada_for_balance(root, p, level); - if (sret) - goto again; - btrfs_set_path_blocking(p); + reada_for_balance(root, p, level); sret = balance_level(trans, root, p, level); btrfs_clear_path_blocking(p, NULL, 0); -- 2.30.2