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authorMichel Lespinasse <walken@google.com>2012-10-08 16:31:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 16:22:37 +0900
commit14b94af0b251a2c80885b60538166fb7d04a642e (patch)
treeef447d340435c441f8c3e54eb8f26f747aa73108 /include/linux/rbtree.h
parentdadf93534f125b9eda486b471446a8456a603d27 (diff)
rbtree: faster augmented rbtree manipulation
Introduce new augmented rbtree APIs that allow minimal recalculation of augmented node information. A new callback is added to the rbtree insertion and erase rebalancing functions, to be called on each tree rotations. Such rotations preserve the subtree's root augmented value, but require recalculation of the one child that was previously located at the subtree root. In the insertion case, the handcoded search phase must be updated to maintain the augmented information on insertion, and then the rbtree coloring/rebalancing algorithms keep it up to date. In the erase case, things are more complicated since it is library code that manipulates the rbtree in order to remove internal nodes. This requires a couple additional callbacks to copy a subtree's augmented value when a new root is stitched in, and to recompute augmented values down the ancestry path when a node is removed from the tree. In order to preserve maximum speed for the non-augmented case, we provide two versions of each tree manipulation function. rb_insert_augmented() is the augmented equivalent of rb_insert_color(), and rb_erase_augmented() is the augmented equivalent of rb_erase(). Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw2@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.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index bf836a2c6a32..c902eb9d6506 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -61,6 +61,25 @@ struct rb_root {
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);
+
+struct rb_augment_callbacks {
+ void (*propagate)(struct rb_node *node, struct rb_node *stop);
+ void (*copy)(struct rb_node *old, struct rb_node *new);
+ void (*rotate)(struct rb_node *old, struct rb_node *new);
+};
+
+extern void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+ void (*augment_rotate)(struct rb_node *old, struct rb_node *new));
+extern void rb_erase_augmented(struct rb_node *node, struct rb_root *root,
+ const struct rb_augment_callbacks *augment);
+static inline void
+rb_insert_augmented(struct rb_node *node, struct rb_root *root,
+ const struct rb_augment_callbacks *augment)
+{
+ __rb_insert_augmented(node, root, augment->rotate);
+}
+
+
typedef void (*rb_augment_f)(struct rb_node *node, void *data);
extern void rb_augment_insert(struct rb_node *node,