rb_first_cached() trades an extra pointer "leftmost" for doing the
same job as rb_first() but in O(1).
As evict_inode_truncate_pages() removes all extent mapping by always
looking for the first rb entry, it's helpful to use rb_first_cached
instead.
Signed-off-by: Liu Bo <bo....@linux.alibaba.com>
---
fs/btrfs/extent_map.c | 27 +++++++++++++++------------
fs/btrfs/extent_map.h | 2 +-
fs/btrfs/inode.c | 4 ++--
fs/btrfs/tests/extent-map-tests.c | 4 ++--
fs/btrfs/volumes.c | 5 +++--
5 files changed, 23 insertions(+), 19 deletions(-)
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index 6648d55e5339..819420eab91d 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -34,7 +34,7 @@ void __cold extent_map_exit(void)
*/
void extent_map_tree_init(struct extent_map_tree *tree)
{
- tree->map = RB_ROOT;
+ tree->map = RB_ROOT_CACHED;
INIT_LIST_HEAD(&tree->modified_extents);
rwlock_init(&tree->lock);
}
@@ -90,24 +90,27 @@ static u64 range_end(u64 start, u64 len)
return start + len;
}
-static int tree_insert(struct rb_root *root, struct extent_map *em)
+static int tree_insert(struct rb_root_cached *root, struct extent_map *em)
{
- struct rb_node **p = &root->rb_node;
+ struct rb_node **p = &root->rb_root.rb_node;
struct rb_node *parent = NULL;
struct extent_map *entry = NULL;
struct rb_node *orig_parent = NULL;
u64 end = range_end(em->start, em->len);
+ bool leftmost = true;
while (*p) {
parent = *p;
entry = rb_entry(parent, struct extent_map, rb_node);
- if (em->start < entry->start)
+ if (em->start < entry->start) {
p = &(*p)->rb_left;
- else if (em->start >= extent_map_end(entry))
+ } else if (em->start >= extent_map_end(entry)) {
p = &(*p)->rb_right;
- else
+ leftmost = false;
+ } else {
return -EEXIST;
+ }
}
orig_parent = parent;
@@ -130,7 +133,7 @@ static int tree_insert(struct rb_root *root, struct
extent_map *em)
return -EEXIST;
rb_link_node(&em->rb_node, orig_parent, p);
- rb_insert_color(&em->rb_node, root);
+ rb_insert_color_cached(&em->rb_node, root, leftmost);
return 0;
}
@@ -242,7 +245,7 @@ static void try_merge_map(struct extent_map_tree *tree,
struct extent_map *em)
em->mod_start = merge->mod_start;
em->generation = max(em->generation, merge->generation);
- rb_erase(&merge->rb_node, &tree->map);
+ rb_erase_cached(&merge->rb_node, &tree->map);
RB_CLEAR_NODE(&merge->rb_node);
free_extent_map(merge);
}
@@ -254,7 +257,7 @@ static void try_merge_map(struct extent_map_tree *tree,
struct extent_map *em)
if (rb && mergable_maps(em, merge)) {
em->len += merge->len;
em->block_len += merge->block_len;
- rb_erase(&merge->rb_node, &tree->map);
+ rb_erase_cached(&merge->rb_node, &tree->map);
RB_CLEAR_NODE(&merge->rb_node);
em->mod_len = (merge->mod_start + merge->mod_len) -
em->mod_start;
em->generation = max(em->generation, merge->generation);
@@ -367,7 +370,7 @@ int add_extent_mapping(struct extent_map_tree *tree,
struct rb_node *next = NULL;
u64 end = range_end(start, len);
- rb_node = __tree_search(&tree->map, start, &prev, &next);
+ rb_node = __tree_search(&tree->map.rb_root, start, &prev, &next);
if (!rb_node) {
if (prev)
rb_node = prev;
@@ -433,7 +436,7 @@ int remove_extent_mapping(struct extent_map_tree *tree,
struct extent_map *em)
int ret = 0;
WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
- rb_erase(&em->rb_node, &tree->map);
+ rb_erase_cached(&em->rb_node, &tree->map);
if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
list_del_init(&em->list);
RB_CLEAR_NODE(&em->rb_node);
@@ -449,7 +452,7 @@ void replace_extent_mapping(struct extent_map_tree *tree,
ASSERT(extent_map_in_tree(cur));
if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags))
list_del_init(&cur->list);
- rb_replace_node(&cur->rb_node, &new->rb_node, &tree->map);
+ rb_replace_node_cached(&cur->rb_node, &new->rb_node, &tree->map);
RB_CLEAR_NODE(&cur->rb_node);
setup_extent_mapping(tree, new, modified);
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index 25d985e7532a..6afe786bf6d0 100644
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -49,7 +49,7 @@ struct extent_map {
};
struct extent_map_tree {
- struct rb_root map;
+ struct rb_root_cached map;
struct list_head modified_extents;
rwlock_t lock;
};
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6e761cec1f2a..10e86f7b5398 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5252,10 +5252,10 @@ static void evict_inode_truncate_pages(struct inode
*inode)
truncate_inode_pages_final(&inode->i_data);
write_lock(&map_tree->lock);
- while (!RB_EMPTY_ROOT(&map_tree->map)) {
+ while (!RB_EMPTY_ROOT(&map_tree->map.rb_root)) {
struct extent_map *em;
- node = rb_first(&map_tree->map);
+ node = rb_first_cached(&map_tree->map);
em = rb_entry(node, struct extent_map, rb_node);
clear_bit(EXTENT_FLAG_PINNED, &em->flags);
clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
diff --git a/fs/btrfs/tests/extent-map-tests.c
b/fs/btrfs/tests/extent-map-tests.c
index 385a5316e4bf..bf15d3a7f20e 100644
--- a/fs/btrfs/tests/extent-map-tests.c
+++ b/fs/btrfs/tests/extent-map-tests.c
@@ -12,8 +12,8 @@ static void free_extent_map_tree(struct extent_map_tree
*em_tree)
struct extent_map *em;
struct rb_node *node;
- while (!RB_EMPTY_ROOT(&em_tree->map)) {
- node = rb_first(&em_tree->map);
+ while (!RB_EMPTY_ROOT(&em_tree->map.rb_root)) {
+ node = rb_first_cached(&em_tree->map);
em = rb_entry(node, struct extent_map, rb_node);
remove_extent_mapping(em_tree, em);
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index da86706123ff..24d37d22a361 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -1613,7 +1613,7 @@ static u64 find_next_chunk(struct btrfs_fs_info *fs_info)
em_tree = &fs_info->mapping_tree.map_tree;
read_lock(&em_tree->lock);
- n = rb_last(&em_tree->map);
+ n = rb_last(&em_tree->map.rb_root);
if (n) {
em = rb_entry(n, struct extent_map, rb_node);
ret = em->start + em->len;
@@ -7433,7 +7433,8 @@ static int verify_chunk_dev_extent_mapping(struct
btrfs_fs_info *fs_info)
int ret = 0;
read_lock(&em_tree->lock);
- for (node = rb_first(&em_tree->map); node; node = rb_next(node)) {
+ for (node = rb_first_cached(&em_tree->map); node;
+ node = rb_next(node)) {
em = rb_entry(node, struct extent_map, rb_node);
if (em->map_lookup->num_stripes !=
em->map_lookup->verified_stripes) {
--
1.8.3.1
