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Commit d7fc640e authored by Chris Mason's avatar Chris Mason
Browse files

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: default avatarChris Mason <chris.mason@oracle.com>
parent 9afbb0b7

fs/btrfs/extent-tree.c

+24 −10
Original line number Diff line number Diff line
@@ -188,9 +188,10 @@ static u64 noinline find_search_start(struct btrfs_root *root, 
{

	int ret;

	struct btrfs_block_group_cache *cache = *cache_ret;

	struct extent_io_tree *free_space_cache;

	struct extent_state *state;

	u64 last;

	u64 start = 0;

	u64 end = 0;

	u64 cache_miss = 0;

	u64 total_fs_bytes;

	int wrapped = 0;
@@ -199,6 +200,8 @@ static u64 noinline find_search_start(struct btrfs_root *root, 
		goto out;

	}

	total_fs_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);

	free_space_cache = &root->fs_info->free_space_cache;



again:

	ret = cache_block_group(root, cache);

	if (ret)
@@ -206,22 +209,27 @@ again: 


	last = max(search_start, cache->key.objectid);



	spin_lock_irq(&free_space_cache->lock);

	state = find_first_extent_bit_state(free_space_cache, last, EXTENT_DIRTY);

	while(1) {

		ret = find_first_extent_bit(&root->fs_info->free_space_cache,

					    last, &start, &end, EXTENT_DIRTY);

		if (ret) {

		if (!state) {

			if (!cache_miss)

				cache_miss = last;

			spin_unlock_irq(&free_space_cache->lock);

			goto new_group;

		}



		start = max(last, start);

		last = end + 1;

		start = max(last, state->start);

		last = state->end + 1;

		if (last - start < num) {

			if (last == cache->key.objectid + cache->key.offset)

				cache_miss = start;

			do {

				state = extent_state_next(state);

			} while(state && !(state->state & EXTENT_DIRTY));

			continue;

		}

		spin_unlock_irq(&free_space_cache->lock);

		if (data != BTRFS_BLOCK_GROUP_MIXED &&

		    start + num > cache->key.objectid + cache->key.offset)

			goto new_group;
@@ -1420,6 +1428,7 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, 
	struct btrfs_block_group_cache *block_group;

	int full_scan = 0;

	int wrapped = 0;

	int empty_cluster;

	u64 cached_start;



	WARN_ON(num_bytes < root->sectorsize);
@@ -1431,11 +1440,15 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, 
		data = BTRFS_BLOCK_GROUP_MIXED;

	}



	if (!data)

	if (!data) {

		last_ptr = &root->fs_info->last_alloc;

		empty_cluster = 128 * 1024;

	}



	if (data && btrfs_test_opt(root, SSD))

	if (data && btrfs_test_opt(root, SSD)) {

		last_ptr = &root->fs_info->last_data_alloc;

		empty_cluster = 2 * 1024 * 1024;

	}



	if (last_ptr) {

		if (*last_ptr)
@@ -1443,8 +1456,9 @@ static int noinline find_free_extent(struct btrfs_trans_handle *trans, 
		else {

			hint_byte = hint_byte &

				~((u64)BTRFS_BLOCK_GROUP_SIZE - 1);

			empty_size += 2 * 1024 * 1024;

			empty_size += empty_cluster;

		}

		search_start = max(search_start, hint_byte);

	}



	search_end = min(search_end,
@@ -1476,7 +1490,7 @@ check_failed: 
	if (last_ptr && *last_ptr && search_start != *last_ptr) {

		*last_ptr = 0;

		if (!empty_size) {

			empty_size += 2 * 1024 * 1024;

			empty_size += empty_cluster;

			total_needed += empty_size;

		}

		search_start = find_search_start(root, &block_group,

fs/btrfs/extent_io.c

+34 −4
Original line number Diff line number Diff line
@@ -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)

{

fs/btrfs/extent_io.h

+11 −0
Original line number Diff line number Diff line
@@ -81,6 +81,15 @@ struct extent_buffer { 


struct extent_map_tree;



static inline struct extent_state *extent_state_next(struct extent_state *state)

{

	struct rb_node *node;

	node = rb_next(&state->rb_node);

	if (!node)

		return NULL;

	return rb_entry(node, struct extent_state, rb_node);

}



typedef struct extent_map *(get_extent_t)(struct inode *inode,

					  struct page *page,

					  size_t page_offset,
@@ -122,6 +131,8 @@ int set_extent_delalloc(struct extent_io_tree *tree, u64 start, u64 end, 
		     gfp_t mask);

int find_first_extent_bit(struct extent_io_tree *tree, u64 start,

			  u64 *start_ret, u64 *end_ret, int bits);

struct extent_state *find_first_extent_bit_state(struct extent_io_tree *tree,

						 u64 start, int bits);

int extent_invalidatepage(struct extent_io_tree *tree,

			  struct page *page, unsigned long offset);

int extent_write_full_page(struct extent_io_tree *tree, struct page *page,

fs/btrfs/disk-io.c

+1 −1

File changed.

Contains only whitespace changes.