Re: [RFC PATCH 1/3] Weight-balanced tree

[Avi Kivity <avi@redhat.com>]

On 02/22/2011 08:55 PM, Alex Williamson wrote:
> Signed-off-by: Alex Williamson<alex.williamson@redhat.com>
> ---
>
>   include/linux/wbtree.h |   55 ++++++++++++++++
>   lib/Makefile           |    3 +
>   lib/wbtree.c           |  170 ++++++++++++++++++++++++++++++++++++++++++++++++
>   3 files changed, 227 insertions(+), 1 deletions(-)
>   create mode 100644 include/linux/wbtree.h
>   create mode 100644 lib/wbtree.c
>

Andrew, can we add something like this to the tree?  Can it go through 
the kvm tree?

> diff --git a/include/linux/wbtree.h b/include/linux/wbtree.h
> new file mode 100644
> index 0000000..ef70f6f
> --- /dev/null
> +++ b/include/linux/wbtree.h
> @@ -0,0 +1,55 @@
> +/*
> + * Weight-balanced binary tree
> + *
> + * The balance of this tree is based on search probability.  The
> + * heaviest weighted nodes (the ones we're most likely to hit), are
> + * at the top of each subtree.
> + *
> + * Copywrite (C) 2011 Red Hat, Inc.
> + *
> + * Authors:
> + *   Alex Williamson<alex.williamson@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +#ifndef _LINUX_WBTREE_H
> +#define _LINUX_WBTREE_H
> +
> +#include<linux/kernel.h>
> +#include<linux/stddef.h>
> +
> +struct wb_node {
> +	struct wb_node *wb_parent;
> +	struct wb_node *wb_left;
> +	struct wb_node *wb_right;
> +	unsigned long wb_weight;
> +};
> +
> +struct wb_root {
> +	struct wb_node *wb_node;
> +};
> +
> +#define WB_ROOT (struct wb_root) { NULL, }
> +#define wb_entry(ptr, type, member) container_of(ptr, type, member)
> +
> +extern void wb_rebalance(struct wb_node *node, struct wb_root *root);
> +extern void wb_erase(struct wb_node *node, struct wb_root *root);
> +extern struct wb_node *wb_first(struct wb_root *root);
> +extern struct wb_node *wb_last(struct wb_root *root);
> +extern struct wb_node *wb_next(struct wb_node *node);
> +extern struct wb_node *wb_prev(struct wb_node *node);
> +
> +static inline void wb_set_weight(struct wb_node *node, unsigned long weight)
> +{
> +	node->wb_weight = weight;
> +}
> +
> +static inline void wb_link_node(struct wb_node *node, struct wb_node *parent,
> +				struct wb_node **wb_link)
> +{
> +	node->wb_left = node->wb_right = NULL;
> +	node->wb_parent = parent;
> +	*wb_link = node;
> +}
> +#endif /* _LINUX_WBTREE_H */
> diff --git a/lib/Makefile b/lib/Makefile
> index cbb774f..5c42e63 100644
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -21,7 +21,8 @@ lib-y	+= kobject.o kref.o klist.o
>
>   obj-y += bcd.o div64.o sort.o parser.o halfmd4.o debug_locks.o random32.o \
>   	 bust_spinlocks.o hexdump.o kasprintf.o bitmap.o scatterlist.o \
> -	 string_helpers.o gcd.o lcm.o list_sort.o uuid.o flex_array.o
> +	 string_helpers.o gcd.o lcm.o list_sort.o uuid.o flex_array.o \
> +	 wbtree.o
>

obj-$(CONFIG_WEIGHT_BALANCED_TREE) += wbtree.o

then kvm can select it, and the impact on non-kvm kernels is removed.

>   ifeq ($(CONFIG_DEBUG_KOBJECT),y)
>   CFLAGS_kobject.o += -DDEBUG
> diff --git a/lib/wbtree.c b/lib/wbtree.c
> new file mode 100644
> index 0000000..54c3817
> --- /dev/null
> +++ b/lib/wbtree.c
> @@ -0,0 +1,170 @@
> +/*
> + * Weight-balanced binary tree
> + *
> + * The balance of this tree is based on search probability.  The
> + * heaviest weighted nodes (the ones we're most likely to hit), are
> + * at the top of each subtree.
> + *
> + * Copywrite (C) 2011 Red Hat, Inc.
> + *
> + * Authors:
> + *   Alex Williamson<alex.williamson@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2.  See
> + * the COPYING file in the top-level directory.
> + */
> +#include<linux/wbtree.h>
> +#include<linux/module.h>
> +
> +static void __wb_rotate_left(struct wb_node *node, struct wb_root *root)
> +{
> +	struct wb_node *right = node->wb_right;
> +	struct wb_node *parent = node->wb_parent;
> +
> +	if ((node->wb_right = right->wb_left))
> +		right->wb_left->wb_parent = node;
> +	right->wb_left = node;
> +
> +	right->wb_parent = parent;
> +
> +	if (parent) {
> +		if (node == parent->wb_left)
> +			parent->wb_left = right;
> +		else
> +			parent->wb_right = right;
> +	} else
> +		root->wb_node = right;
> +
> +	node->wb_parent = right;
> +}
> +
> +static void __wb_rotate_right(struct wb_node *node, struct wb_root *root)
> +{
> +	struct wb_node *left = node->wb_left;
> +	struct wb_node *parent = node->wb_parent;
> +
> +	if ((node->wb_left = left->wb_right))
> +		left->wb_right->wb_parent = node;
> +	left->wb_right = node;
> +
> +	left->wb_parent = parent;
> +
> +	if (parent) {
> +		if (node == parent->wb_right)
> +			parent->wb_right = left;
> +		else
> +			parent->wb_left = left;
> +	} else
> +		root->wb_node = left;
> +
> +	node->wb_parent = left;
> +}
> +
> +void wb_rebalance(struct wb_node *node, struct wb_root *root)
> +{
> +	while (node->wb_parent&&  node->wb_parent->wb_weight<  node->wb_weight) {
> +		if (node == node->wb_parent->wb_left)
> +			__wb_rotate_right(node->wb_parent, root);
> +		else
> +			__wb_rotate_left(node->wb_parent, root);
> +	}
> +}
> +EXPORT_SYMBOL(wb_rebalance);
> +
> +void wb_erase(struct wb_node *node, struct wb_root *root)
> +{
> +	while (node->wb_left || node->wb_right) {
> +		if (!node->wb_left)
> +			__wb_rotate_left(node, root);
> +		else if (!node->wb_right)
> +			__wb_rotate_right(node, root);
> +		else {
> +			if (node->wb_left->wb_weight>
> +			    node->wb_right->wb_weight)
> +				__wb_rotate_right(node, root);
> +			else
> +				__wb_rotate_left(node, root);
> +		}
> +	}
> +
> +	if (node->wb_parent) {
> +		if (node->wb_parent->wb_left == node)
> +			node->wb_parent->wb_left = NULL;
> +		else
> +			node->wb_parent->wb_right = NULL;
> +	} else
> +		root->wb_node = NULL;
> +}
> +EXPORT_SYMBOL(wb_erase);
> +
> +struct wb_node *wb_first(struct wb_root *root)
> +{
> +	struct wb_node *node;
> +
> +	node = root->wb_node;
> +	if (!node)
> +		return NULL;
> +
> +	while (node->wb_left)
> +		node = node->wb_left;
> +
> +	return node;
> +}
> +EXPORT_SYMBOL(wb_first);
> +
> +struct wb_node *wb_last(struct wb_root *root)
> +{
> +	struct wb_node *node;
> +
> +	node = root->wb_node;
> +	if (!node)
> +		return NULL;
> +
> +	while (node->wb_right)
> +		node = node->wb_right;
> +
> +	return node;
> +}
> +EXPORT_SYMBOL(wb_last);
> +
> +struct wb_node *wb_next(struct wb_node *node)
> +{
> +	struct wb_node *parent;
> +
> +	if (node->wb_parent == node)
> +		return NULL;
> +
> +	if (node->wb_right) {
> +		node = node->wb_right;
> +		while (node->wb_left)
> +			node = node->wb_left;
> +		return node;
> +	}
> +
> +	while ((parent = node->wb_parent)&&  node == parent->wb_right)
> +		node = parent;
> +
> +	return parent;
> +}
> +EXPORT_SYMBOL(wb_next);
> +
> +struct wb_node *wb_prev(struct wb_node *node)
> +{
> +	struct wb_node *parent;
> +
> +	if (node->wb_parent == node)
> +		return NULL;
> +
> +	if (node->wb_left) {
> +		node = node->wb_left;
> +		while (node->wb_right)
> +			node = node->wb_right;
> +		return node;
> +	}
> +
> +	while ((parent = node->wb_parent)&&  node == parent->wb_left)
> +		node = parent;
> +
> +	return parent;
> +}
> +EXPORT_SYMBOL(wb_prev);
>


-- 
error compiling committee.c: too many arguments to function