Commit 99d4d265 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

rbtree: Add rb_add_augmented_cached() helper 



While slightly sub-optimal, updating the augmented data while going
down the tree during lookup would be faster -- alas the augment
interface does not currently allow for that, provide a generic helper
to add a node to an augmented cached tree.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20230531124603.862983648@infradead.org
parent 86bfbb7c

include/linux/rbtree_augmented.h

+26 −0
Original line number Diff line number Diff line
@@ -60,6 +60,32 @@ rb_insert_augmented_cached(struct rb_node *node, 
	rb_insert_augmented(node, &root->rb_root, augment);

}



static __always_inline struct rb_node *

rb_add_augmented_cached(struct rb_node *node, struct rb_root_cached *tree,

			bool (*less)(struct rb_node *, const struct rb_node *),

			const struct rb_augment_callbacks *augment)

{

	struct rb_node **link = &tree->rb_root.rb_node;

	struct rb_node *parent = NULL;

	bool leftmost = true;



	while (*link) {

		parent = *link;

		if (less(node, parent)) {

			link = &parent->rb_left;

		} else {

			link = &parent->rb_right;

			leftmost = false;

		}

	}



	rb_link_node(node, parent, link);

	augment->propagate(parent, NULL); /* suboptimal */

	rb_insert_augmented_cached(node, tree, leftmost, augment);



	return leftmost ? node : NULL;

}



/*

 * Template for declaring augmented rbtree callbacks (generic case)

 *