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authorMichel Lespinasse <walken@google.com>2019-07-17 02:27:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-17 05:23:22 +0300
commit9f973cb38088e0cf42e0bae97ff140813e623f13 (patch)
treeeee4545125e037873c8bf29ec1d5ff6064d2e456 /include/linux/rbtree.h
parent4ab7ace465466d25c12cee9854e7140077e208cb (diff)
downloadlinux-9f973cb38088e0cf42e0bae97ff140813e623f13.tar.xz
lib/rbtree: avoid generating code twice for the cached versions
As was already noted in rbtree.h, the logic to cache rb_first (or rb_last) can easily be implemented externally to the core rbtree api. Change the implementation to do just that. Previously the update of rb_leftmost was wired deeper into the implmentation, but there were some disadvantages to that - mostly, lib/rbtree.c had separate instantiations for rb_insert_color() vs rb_insert_color_cached(), as well as rb_erase() vs rb_erase_cached(), which were doing exactly the same thing save for the rb_leftmost update at the start of either function. text data bss dec hex filename 5405 120 0 5525 1595 lib/rbtree.o-vanilla 3827 96 0 3923 f53 lib/rbtree.o-patch [dave@stgolabs.net: changelog addition] Link: http://lkml.kernel.org/r/20190628171416.by5gdizl3rcxk5h5@linux-r8p5 [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20190628045008.39926-1-walken@google.com Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Davidlohr Bueso <dbueso@suse.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/rbtree.h')
-rw-r--r--include/linux/rbtree.h70
1 files changed, 46 insertions, 24 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index e6337fce08f2..1fd61a9af45c 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -32,25 +32,9 @@ struct rb_root {
struct rb_node *rb_node;
};
-/*
- * Leftmost-cached rbtrees.
- *
- * We do not cache the rightmost node based on footprint
- * size vs number of potential users that could benefit
- * from O(1) rb_last(). Just not worth it, users that want
- * this feature can always implement the logic explicitly.
- * Furthermore, users that want to cache both pointers may
- * find it a bit asymmetric, but that's ok.
- */
-struct rb_root_cached {
- struct rb_root rb_root;
- struct rb_node *rb_leftmost;
-};
-
#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
#define RB_ROOT (struct rb_root) { NULL, }
-#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
@@ -72,12 +56,6 @@ extern struct rb_node *rb_prev(const struct rb_node *);
extern struct rb_node *rb_first(const struct rb_root *);
extern struct rb_node *rb_last(const struct rb_root *);
-extern void rb_insert_color_cached(struct rb_node *,
- struct rb_root_cached *, bool);
-extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
-/* Same as rb_first(), but O(1) */
-#define rb_first_cached(root) (root)->rb_leftmost
-
/* Postorder iteration - always visit the parent after its children */
extern struct rb_node *rb_first_postorder(const struct rb_root *);
extern struct rb_node *rb_next_postorder(const struct rb_node *);
@@ -87,8 +65,6 @@ extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
struct rb_root *root);
extern void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new,
struct rb_root *root);
-extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
- struct rb_root_cached *root);
static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
struct rb_node **rb_link)
@@ -136,4 +112,50 @@ static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent
typeof(*pos), field); 1; }); \
pos = n)
+/*
+ * Leftmost-cached rbtrees.
+ *
+ * We do not cache the rightmost node based on footprint
+ * size vs number of potential users that could benefit
+ * from O(1) rb_last(). Just not worth it, users that want
+ * this feature can always implement the logic explicitly.
+ * Furthermore, users that want to cache both pointers may
+ * find it a bit asymmetric, but that's ok.
+ */
+struct rb_root_cached {
+ struct rb_root rb_root;
+ struct rb_node *rb_leftmost;
+};
+
+#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
+
+/* Same as rb_first(), but O(1) */
+#define rb_first_cached(root) (root)->rb_leftmost
+
+static inline void rb_insert_color_cached(struct rb_node *node,
+ struct rb_root_cached *root,
+ bool leftmost)
+{
+ if (leftmost)
+ root->rb_leftmost = node;
+ rb_insert_color(node, &root->rb_root);
+}
+
+static inline void rb_erase_cached(struct rb_node *node,
+ struct rb_root_cached *root)
+{
+ if (root->rb_leftmost == node)
+ root->rb_leftmost = rb_next(node);
+ rb_erase(node, &root->rb_root);
+}
+
+static inline void rb_replace_node_cached(struct rb_node *victim,
+ struct rb_node *new,
+ struct rb_root_cached *root)
+{
+ if (root->rb_leftmost == victim)
+ root->rb_leftmost = new;
+ rb_replace_node(victim, new, &root->rb_root);
+}
+
#endif /* _LINUX_RBTREE_H */