rb_first_cached() trades an extra pointer "leftmost" for doing the same
job as rb_first() but in O(1).
Functions manipulating delayed_item need to get the first entry, this
converts it to use rb_first_cached().
Signed-off-by: Liu Bo <bo....@linux.alibaba.com>
---
fs/btrfs/delayed-inode.c | 29 ++++++++++++++++-------------
fs/btrfs/delayed-inode.h | 4 ++--
2 files changed, 18 insertions(+), 15 deletions(-)
diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
index db9f45082c61..72569849828e 100644
--- a/fs/btrfs/delayed-inode.c
+++ b/fs/btrfs/delayed-inode.c
@@ -42,8 +42,8 @@ static inline void btrfs_init_delayed_node(
delayed_node->root = root;
delayed_node->inode_id = inode_id;
refcount_set(&delayed_node->refs, 0);
- delayed_node->ins_root = RB_ROOT;
- delayed_node->del_root = RB_ROOT;
+ delayed_node->ins_root = RB_ROOT_CACHED;
+ delayed_node->del_root = RB_ROOT_CACHED;
mutex_init(&delayed_node->mutex);
INIT_LIST_HEAD(&delayed_node->n_list);
INIT_LIST_HEAD(&delayed_node->p_list);
@@ -390,7 +390,7 @@ static struct btrfs_delayed_item
*__btrfs_lookup_delayed_insertion_item(
struct btrfs_delayed_node *delayed_node,
struct btrfs_key *key)
{
- return __btrfs_lookup_delayed_item(&delayed_node->ins_root, key,
+ return __btrfs_lookup_delayed_item(&delayed_node->ins_root.rb_root, key,
NULL, NULL);
}
@@ -400,9 +400,10 @@ static int __btrfs_add_delayed_item(struct
btrfs_delayed_node *delayed_node,
{
struct rb_node **p, *node;
struct rb_node *parent_node = NULL;
- struct rb_root *root;
+ struct rb_root_cached *root;
struct btrfs_delayed_item *item;
int cmp;
+ bool leftmost = true;
if (action == BTRFS_DELAYED_INSERTION_ITEM)
root = &delayed_node->ins_root;
@@ -410,7 +411,7 @@ static int __btrfs_add_delayed_item(struct
btrfs_delayed_node *delayed_node,
root = &delayed_node->del_root;
else
BUG();
- p = &root->rb_node;
+ p = &root->rb_root.rb_node;
node = &ins->rb_node;
while (*p) {
@@ -419,16 +420,18 @@ static int __btrfs_add_delayed_item(struct
btrfs_delayed_node *delayed_node,
rb_node);
cmp = btrfs_comp_cpu_keys(&item->key, &ins->key);
- if (cmp < 0)
+ if (cmp < 0) {
p = &(*p)->rb_right;
- else if (cmp > 0)
+ leftmost = false;
+ } else if (cmp > 0) {
p = &(*p)->rb_left;
- else
+ } else {
return -EEXIST;
+ }
}
rb_link_node(node, parent_node, p);
- rb_insert_color(node, root);
+ rb_insert_color_cached(node, root, leftmost);
ins->delayed_node = delayed_node;
ins->ins_or_del = action;
@@ -468,7 +471,7 @@ static void finish_one_item(struct btrfs_delayed_root
*delayed_root)
static void __btrfs_remove_delayed_item(struct btrfs_delayed_item
*delayed_item)
{
- struct rb_root *root;
+ struct rb_root_cached *root;
struct btrfs_delayed_root *delayed_root;
delayed_root = delayed_item->delayed_node->root->fs_info->delayed_root;
@@ -482,7 +485,7 @@ static void __btrfs_remove_delayed_item(struct
btrfs_delayed_item *delayed_item)
else
root = &delayed_item->delayed_node->del_root;
- rb_erase(&delayed_item->rb_node, root);
+ rb_erase_cached(&delayed_item->rb_node, root);
delayed_item->delayed_node->count--;
finish_one_item(delayed_root);
@@ -503,7 +506,7 @@ static struct btrfs_delayed_item
*__btrfs_first_delayed_insertion_item(
struct rb_node *p;
struct btrfs_delayed_item *item = NULL;
- p = rb_first(&delayed_node->ins_root);
+ p = rb_first_cached(&delayed_node->ins_root);
if (p)
item = rb_entry(p, struct btrfs_delayed_item, rb_node);
@@ -516,7 +519,7 @@ static struct btrfs_delayed_item
*__btrfs_first_delayed_deletion_item(
struct rb_node *p;
struct btrfs_delayed_item *item = NULL;
- p = rb_first(&delayed_node->del_root);
+ p = rb_first_cached(&delayed_node->del_root);
if (p)
item = rb_entry(p, struct btrfs_delayed_item, rb_node);
diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h
index 33536cd681d4..74ae226ffaf0 100644
--- a/fs/btrfs/delayed-inode.h
+++ b/fs/btrfs/delayed-inode.h
@@ -50,8 +50,8 @@ struct btrfs_delayed_node {
* is waiting to be dealt with by the async worker.
*/
struct list_head p_list;
- struct rb_root ins_root;
- struct rb_root del_root;
+ struct rb_root_cached ins_root;
+ struct rb_root_cached del_root;
struct mutex mutex;
struct btrfs_inode_item inode_item;
refcount_t refs;
--
1.8.3.1
