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 <chris.mason@oracle.com>
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 6f0825b..88e21bd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -951,7 +951,7 @@
void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
{
balance_dirty_pages_ratelimited_nr(
- root->fs_info->btree_inode->i_mapping, 1);
+ root->fs_info->btree_inode->i_mapping, 1);
}
void btrfs_set_buffer_defrag(struct extent_buffer *buf)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index af5d4a0..239e9d8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -188,9 +188,10 @@
{
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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,
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 9262ab3..fb64008 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -255,7 +255,7 @@
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 @@
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 @@
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 @@
}
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)
{
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 151fdad..fcc4bb0 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -81,6 +81,15 @@
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 @@
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,