From d7fc640e6fed46932f7c74e14f9b58b8637c66cf Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 18 Feb 2008 12:12:38 -0500 Subject: Btrfs: Allocator improvements Reduce CPU time searching for free blocks by optimizing find_first_extent_bit Fix find_free_extent to make better use of the last_alloc hint. Before it was often finding blocks just before the hint. Signed-off-by: Chris Mason --- fs/btrfs/extent_io.c | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) (limited to 'fs/btrfs/extent_io.c') diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index 9262ab37a7cd..fb6400895ed6 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -255,7 +255,7 @@ static int merge_state(struct extent_io_tree *tree, state->start = other->start; other->tree = NULL; if (tree->last == other) - tree->last = NULL; + tree->last = state; rb_erase(&other->rb_node, &tree->state); free_extent_state(other); } @@ -268,7 +268,7 @@ static int merge_state(struct extent_io_tree *tree, other->start = state->start; state->tree = NULL; if (tree->last == state) - tree->last = NULL; + tree->last = other; rb_erase(&state->rb_node, &tree->state); free_extent_state(state); } @@ -397,8 +397,9 @@ static int clear_state_bit(struct extent_io_tree *tree, if (delete || state->state == 0) { if (state->tree) { clear_state_cb(tree, state, state->state); - if (tree->last == state) - tree->last = NULL; + if (tree->last == state) { + tree->last = extent_state_next(state); + } rb_erase(&state->rb_node, &tree->state); state->tree = NULL; free_extent_state(state); @@ -962,6 +963,35 @@ out: } EXPORT_SYMBOL(find_first_extent_bit); +struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree, + u64 start, int bits) +{ + struct rb_node *node; + struct extent_state *state; + + /* + * this search will find all the extents that end after + * our range starts. + */ + node = tree_search(tree, start); + if (!node || IS_ERR(node)) { + goto out; + } + + while(1) { + state = rb_entry(node, struct extent_state, rb_node); + if (state->end >= start && (state->state & bits)) { + return state; + } + node = rb_next(node); + if (!node) + break; + } +out: + return NULL; +} +EXPORT_SYMBOL(find_first_extent_bit_state); + u64 find_lock_delalloc_range(struct extent_io_tree *tree, u64 *start, u64 *end, u64 max_bytes) { -- cgit v1.2.3