rb_first_cached() trades an extra pointer "leftmost" for doing the same
job as rb_first() but in O(1).
Functions manipulating href->ref_tree need to get the first entry, this
converts href->ref_tree to use rb_first_cached().
Signed-off-by: Liu Bo <bo....@linux.alibaba.com>
---
fs/btrfs/backref.c | 2 +-
fs/btrfs/delayed-ref.c | 24 ++++++++++++++----------
fs/btrfs/delayed-ref.h | 2 +-
fs/btrfs/disk-io.c | 4 ++--
fs/btrfs/extent-tree.c | 13 +++++++------
5 files changed, 25 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index ae750b1574a2..bc1ea6e9ea4f 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -769,7 +769,7 @@ static int add_delayed_refs(const struct btrfs_fs_info
*fs_info,
btrfs_disk_key_to_cpu(&tmp_op_key, &extent_op->key);
spin_lock(&head->lock);
- for (n = rb_first(&head->ref_tree); n; n = rb_next(n)) {
+ for (n = rb_first_cached(&head->ref_tree); n; n = rb_next(n)) {
node = rb_entry(n, struct btrfs_delayed_ref_node,
ref_node);
if (node->seq > seq)
diff --git a/fs/btrfs/delayed-ref.c b/fs/btrfs/delayed-ref.c
index 4ef4a30ccc3d..5f4d46e0f2c0 100644
--- a/fs/btrfs/delayed-ref.c
+++ b/fs/btrfs/delayed-ref.c
@@ -133,13 +133,14 @@ static struct btrfs_delayed_ref_head *htree_insert(struct
rb_root_cached *root,
return NULL;
}
-static struct btrfs_delayed_ref_node* tree_insert(struct rb_root *root,
+static struct btrfs_delayed_ref_node *tree_insert(struct rb_root_cached *root,
struct btrfs_delayed_ref_node *ins)
{
- struct rb_node **p = &root->rb_node;
+ struct rb_node **p = &root->rb_root.rb_node;
struct rb_node *node = &ins->ref_node;
struct rb_node *parent_node = NULL;
struct btrfs_delayed_ref_node *entry;
+ bool leftmost = true;
while (*p) {
int comp;
@@ -148,16 +149,18 @@ static struct btrfs_delayed_ref_node* tree_insert(struct
rb_root *root,
entry = rb_entry(parent_node, struct btrfs_delayed_ref_node,
ref_node);
comp = comp_refs(ins, entry, true);
- if (comp < 0)
+ if (comp < 0) {
p = &(*p)->rb_left;
- else if (comp > 0)
+ } else if (comp > 0) {
p = &(*p)->rb_right;
- else
+ leftmost = false;
+ } else {
return entry;
+ }
}
rb_link_node(node, parent_node, p);
- rb_insert_color(node, root);
+ rb_insert_color_cached(node, root, leftmost);
return NULL;
}
@@ -231,7 +234,7 @@ static inline void drop_delayed_ref(struct
btrfs_trans_handle *trans,
struct btrfs_delayed_ref_node *ref)
{
lockdep_assert_held(&head->lock);
- rb_erase(&ref->ref_node, &head->ref_tree);
+ rb_erase_cached(&ref->ref_node, &head->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
@@ -300,7 +303,7 @@ void btrfs_merge_delayed_refs(struct btrfs_trans_handle
*trans,
lockdep_assert_held(&head->lock);
- if (RB_EMPTY_ROOT(&head->ref_tree))
+ if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
return;
/* We don't have too many refs to merge for data. */
@@ -318,7 +321,8 @@ void btrfs_merge_delayed_refs(struct btrfs_trans_handle
*trans,
spin_unlock(&fs_info->tree_mod_seq_lock);
again:
- for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
+ for (node = rb_first_cached(&head->ref_tree); node;
+ node = rb_next(node)) {
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
if (seq && ref->seq >= seq)
continue;
@@ -573,7 +577,7 @@ static void init_delayed_ref_head(struct
btrfs_delayed_ref_head *head_ref,
head_ref->must_insert_reserved = must_insert_reserved;
head_ref->is_data = is_data;
head_ref->is_system = is_system;
- head_ref->ref_tree = RB_ROOT;
+ head_ref->ref_tree = RB_ROOT_CACHED;
INIT_LIST_HEAD(&head_ref->ref_add_list);
RB_CLEAR_NODE(&head_ref->href_node);
head_ref->processing = 0;
diff --git a/fs/btrfs/delayed-ref.h b/fs/btrfs/delayed-ref.h
index 88438b6cee45..c3e3486a126c 100644
--- a/fs/btrfs/delayed-ref.h
+++ b/fs/btrfs/delayed-ref.h
@@ -79,7 +79,7 @@ struct btrfs_delayed_ref_head {
struct mutex mutex;
spinlock_t lock;
- struct rb_root ref_tree;
+ struct rb_root_cached ref_tree;
/* accumulate add BTRFS_ADD_DELAYED_REF nodes to this ref_add_list. */
struct list_head ref_add_list;
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index dee7bcc13ffa..95a3d33a0454 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -4221,11 +4221,11 @@ static int btrfs_destroy_delayed_refs(struct
btrfs_transaction *trans,
continue;
}
spin_lock(&head->lock);
- while ((n = rb_first(&head->ref_tree)) != NULL) {
+ while ((n = rb_first_cached(&head->ref_tree)) != NULL) {
ref = rb_entry(n, struct btrfs_delayed_ref_node,
ref_node);
ref->in_tree = 0;
- rb_erase(&ref->ref_node, &head->ref_tree);
+ rb_erase_cached(&ref->ref_node, &head->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 0b0472bc209d..e3ee3b7746a8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2374,7 +2374,7 @@ static int run_one_delayed_ref(struct btrfs_trans_handle
*trans,
{
struct btrfs_delayed_ref_node *ref;
- if (RB_EMPTY_ROOT(&head->ref_tree))
+ if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
return NULL;
/*
@@ -2387,7 +2387,7 @@ static int run_one_delayed_ref(struct btrfs_trans_handle
*trans,
return list_first_entry(&head->ref_add_list,
struct btrfs_delayed_ref_node, add_list);
- ref = rb_entry(rb_first(&head->ref_tree),
+ ref = rb_entry(rb_first_cached(&head->ref_tree),
struct btrfs_delayed_ref_node, ref_node);
ASSERT(list_empty(&ref->add_list));
return ref;
@@ -2448,7 +2448,7 @@ static int cleanup_ref_head(struct btrfs_trans_handle
*trans,
spin_unlock(&head->lock);
spin_lock(&delayed_refs->lock);
spin_lock(&head->lock);
- if (!RB_EMPTY_ROOT(&head->ref_tree) || head->extent_op) {
+ if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
spin_unlock(&head->lock);
spin_unlock(&delayed_refs->lock);
return 1;
@@ -2597,7 +2597,7 @@ static noinline int __btrfs_run_delayed_refs(struct
btrfs_trans_handle *trans,
actual_count++;
ref->in_tree = 0;
- rb_erase(&ref->ref_node, &locked_ref->ref_tree);
+ rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
RB_CLEAR_NODE(&ref->ref_node);
if (!list_empty(&ref->add_list))
list_del(&ref->add_list);
@@ -3040,7 +3040,8 @@ static noinline int check_delayed_ref(struct btrfs_root
*root,
* XXX: We should replace this with a proper search function in the
* future.
*/
- for (node = rb_first(&head->ref_tree); node; node = rb_next(node)) {
+ for (node = rb_first_cached(&head->ref_tree); node;
+ node = rb_next(node)) {
ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
/* If it's a shared ref we know a cross reference exists */
if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
@@ -6926,7 +6927,7 @@ static noinline int check_ref_cleanup(struct
btrfs_trans_handle *trans,
goto out_delayed_unlock;
spin_lock(&head->lock);
- if (!RB_EMPTY_ROOT(&head->ref_tree))
+ if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
goto out;
if (head->extent_op) {
--
1.8.3.1
