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Commit 55a98102 authored by David Woodhouse's avatar David Woodhouse
Browse files

[RBTREE] Merge colour and parent fields of struct rb_node. 



We only used a single bit for colour information, so having a whole
machine word of space allocated for it was a bit wasteful. Instead,
store it in the lowest bit of the 'parent' pointer, since that was
always going to be aligned anyway.

Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 1975e593

include/linux/rbtree.h

+19 −13
Original line number Diff line number Diff line
@@ -99,28 +99,35 @@ static inline struct page * rb_insert_page_cache(struct inode * inode, 


struct rb_node

{

	struct rb_node *rb_parent;

	int rb_color;

	unsigned long  rb_parent_colour;

#define	RB_RED		0

#define	RB_BLACK	1

	struct rb_node *rb_right;

	struct rb_node *rb_left;

};



#define rb_parent(r)		((r)->rb_parent)

#define rb_set_parent(r,p)	do { (r)->rb_parent = p; } while (0)

#define rb_colour(r)		((r)->rb_colour)

#define rb_is_red(r)		((r)->colour == RB_RED)

#define rb_is_black(r)		((r)->colour == RB_BLACK)

#define rb_set_red(r)		do { (r)->colour = RB_RED; } while (0)

#define rb_set_black(r)		do { (r)->colour = RB_BLACK; } while (0)

#define rb_set_colour(r,c)	do { (r)->colour = (c); } while (0)



struct rb_root

{

	struct rb_node *rb_node;

};





#define rb_parent(r)   ((struct rb_node *)((r)->rb_parent_colour & ~3))

#define rb_colour(r)   ((r)->rb_parent_colour & 1)

#define rb_is_red(r)   (!rb_colour(r))

#define rb_is_black(r) rb_colour(r)

#define rb_set_red(r)  do { (r)->rb_parent_colour &= ~1; } while (0)

#define rb_set_black(r)  do { (r)->rb_parent_colour |= 1; } while (0)



static inline void rb_set_parent(struct rb_node *rb, struct rb_node *p)

{

	rb->rb_parent_colour = (rb->rb_parent_colour & 3) | (unsigned long)p;

}

static inline void rb_set_colour(struct rb_node *rb, int colour)

{

	rb->rb_parent_colour = (rb->rb_parent_colour & ~1) | colour;

}



#define RB_ROOT	(struct rb_root) { NULL, }

#define	rb_entry(ptr, type, member) container_of(ptr, type, member)
@@ -140,8 +147,7 @@ extern void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
static inline void rb_link_node(struct rb_node * node, struct rb_node * parent,

				struct rb_node ** rb_link)

{

	node->rb_parent = parent;

	node->rb_color = RB_RED;

	node->rb_parent_colour = (unsigned long )parent;

	node->rb_left = node->rb_right = NULL;



	*rb_link = node;

lib/rbtree.c

+90 −88
Original line number Diff line number Diff line
@@ -26,60 +26,66 @@ 
static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)

{

	struct rb_node *right = node->rb_right;

	struct rb_node *parent = rb_parent(node);



	if ((node->rb_right = right->rb_left))

		right->rb_left->rb_parent = node;

		rb_set_parent(right->rb_left, node);

	right->rb_left = node;



	if ((right->rb_parent = node->rb_parent))

	rb_set_parent(right, parent);



	if (parent)

	{

		if (node == node->rb_parent->rb_left)

			node->rb_parent->rb_left = right;

		if (node == parent->rb_left)

			parent->rb_left = right;

		else

			node->rb_parent->rb_right = right;

			parent->rb_right = right;

	}

	else

		root->rb_node = right;

	node->rb_parent = right;

	rb_set_parent(node, right);

}



static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)

{

	struct rb_node *left = node->rb_left;

	struct rb_node *parent = rb_parent(node);



	if ((node->rb_left = left->rb_right))

		left->rb_right->rb_parent = node;

		rb_set_parent(left->rb_right, node);

	left->rb_right = node;



	if ((left->rb_parent = node->rb_parent))

	rb_set_parent(left, parent);



	if (parent)

	{

		if (node == node->rb_parent->rb_right)

			node->rb_parent->rb_right = left;

		if (node == parent->rb_right)

			parent->rb_right = left;

		else

			node->rb_parent->rb_left = left;

			parent->rb_left = left;

	}

	else

		root->rb_node = left;

	node->rb_parent = left;

	rb_set_parent(node, left);

}



void rb_insert_color(struct rb_node *node, struct rb_root *root)

{

	struct rb_node *parent, *gparent;



	while ((parent = node->rb_parent) && parent->rb_color == RB_RED)

	while ((parent = rb_parent(node)) && rb_is_red(parent))

	{

		gparent = parent->rb_parent;

		gparent = rb_parent(parent);



		if (parent == gparent->rb_left)

		{

			{

				register struct rb_node *uncle = gparent->rb_right;

				if (uncle && uncle->rb_color == RB_RED)

				if (uncle && rb_is_red(uncle))

				{

					uncle->rb_color = RB_BLACK;

					parent->rb_color = RB_BLACK;

					gparent->rb_color = RB_RED;

					rb_set_black(uncle);

					rb_set_black(parent);

					rb_set_red(gparent);

					node = gparent;

					continue;

				}
@@ -94,17 +100,17 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root) 
				node = tmp;

			}



			parent->rb_color = RB_BLACK;

			gparent->rb_color = RB_RED;

			rb_set_black(parent);

			rb_set_red(gparent);

			__rb_rotate_right(gparent, root);

		} else {

			{

				register struct rb_node *uncle = gparent->rb_left;

				if (uncle && uncle->rb_color == RB_RED)

				if (uncle && rb_is_red(uncle))

				{

					uncle->rb_color = RB_BLACK;

					parent->rb_color = RB_BLACK;

					gparent->rb_color = RB_RED;

					rb_set_black(uncle);

					rb_set_black(parent);

					rb_set_red(gparent);

					node = gparent;

					continue;

				}
@@ -119,13 +125,13 @@ void rb_insert_color(struct rb_node *node, struct rb_root *root) 
				node = tmp;

			}



			parent->rb_color = RB_BLACK;

			gparent->rb_color = RB_RED;

			rb_set_black(parent);

			rb_set_red(gparent);

			__rb_rotate_left(gparent, root);

		}

	}



	root->rb_node->rb_color = RB_BLACK;

	rb_set_black(root->rb_node);

}

EXPORT_SYMBOL(rb_insert_color);
@@ -134,43 +140,40 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, 
{

	struct rb_node *other;



	while ((!node || node->rb_color == RB_BLACK) && node != root->rb_node)

	while ((!node || rb_is_black(node)) && node != root->rb_node)

	{

		if (parent->rb_left == node)

		{

			other = parent->rb_right;

			if (other->rb_color == RB_RED)

			if (rb_is_red(other))

			{

				other->rb_color = RB_BLACK;

				parent->rb_color = RB_RED;

				rb_set_black(other);

				rb_set_red(parent);

				__rb_rotate_left(parent, root);

				other = parent->rb_right;

			}

			if ((!other->rb_left ||

			     other->rb_left->rb_color == RB_BLACK)

			    && (!other->rb_right ||

				other->rb_right->rb_color == RB_BLACK))

			if ((!other->rb_left || rb_is_black(other->rb_left)) &&

			    (!other->rb_right || rb_is_black(other->rb_right)))

			{

				other->rb_color = RB_RED;

				rb_set_red(other);

				node = parent;

				parent = node->rb_parent;

				parent = rb_parent(node);

			}

			else

			{

				if (!other->rb_right ||

				    other->rb_right->rb_color == RB_BLACK)

				if (!other->rb_right || rb_is_black(other->rb_right))

				{

					register struct rb_node *o_left;

					struct rb_node *o_left;

					if ((o_left = other->rb_left))

						o_left->rb_color = RB_BLACK;

					other->rb_color = RB_RED;

						rb_set_black(o_left);

					rb_set_red(other);

					__rb_rotate_right(other, root);

					other = parent->rb_right;

				}

				other->rb_color = parent->rb_color;

				parent->rb_color = RB_BLACK;

				rb_set_colour(other, rb_colour(parent));

				rb_set_black(parent);

				if (other->rb_right)

					other->rb_right->rb_color = RB_BLACK;

					rb_set_black(other->rb_right);

				__rb_rotate_left(parent, root);

				node = root->rb_node;

				break;
@@ -179,38 +182,35 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, 
		else

		{

			other = parent->rb_left;

			if (other->rb_color == RB_RED)

			if (rb_is_red(other))

			{

				other->rb_color = RB_BLACK;

				parent->rb_color = RB_RED;

				rb_set_black(other);

				rb_set_red(parent);

				__rb_rotate_right(parent, root);

				other = parent->rb_left;

			}

			if ((!other->rb_left ||

			     other->rb_left->rb_color == RB_BLACK)

			    && (!other->rb_right ||

				other->rb_right->rb_color == RB_BLACK))

			if ((!other->rb_left || rb_is_black(other->rb_left)) &&

			    (!other->rb_right || rb_is_black(other->rb_right)))

			{

				other->rb_color = RB_RED;

				rb_set_red(other);

				node = parent;

				parent = node->rb_parent;

				parent = rb_parent(node);

			}

			else

			{

				if (!other->rb_left ||

				    other->rb_left->rb_color == RB_BLACK)

				if (!other->rb_left || rb_is_black(other->rb_left))

				{

					register struct rb_node *o_right;

					if ((o_right = other->rb_right))

						o_right->rb_color = RB_BLACK;

					other->rb_color = RB_RED;

						rb_set_black(o_right);

					rb_set_red(other);

					__rb_rotate_left(other, root);

					other = parent->rb_left;

				}

				other->rb_color = parent->rb_color;

				parent->rb_color = RB_BLACK;

				rb_set_colour(other, rb_colour(parent));

				rb_set_black(parent);

				if (other->rb_left)

					other->rb_left->rb_color = RB_BLACK;

					rb_set_black(other->rb_left);

				__rb_rotate_right(parent, root);

				node = root->rb_node;

				break;
@@ -218,7 +218,7 @@ static void __rb_erase_color(struct rb_node *node, struct rb_node *parent, 
		}

	}

	if (node)

		node->rb_color = RB_BLACK;

		rb_set_black(node);

}



void rb_erase(struct rb_node *node, struct rb_root *root)
@@ -238,43 +238,41 @@ void rb_erase(struct rb_node *node, struct rb_root *root) 
		while ((left = node->rb_left) != NULL)

			node = left;

		child = node->rb_right;

		parent = node->rb_parent;

		color = node->rb_color;

		parent = rb_parent(node);

		color = rb_colour(node);



		if (child)

			child->rb_parent = parent;



		if (node->rb_parent == old) {

			rb_set_parent(child, parent);

		if (parent == old) {

			parent->rb_right = child;

			parent = node;

		} else

			parent->rb_left = child;



		node->rb_parent = old->rb_parent;

		node->rb_color = old->rb_color;

		node->rb_parent_colour = old->rb_parent_colour;

		node->rb_right = old->rb_right;

		node->rb_left = old->rb_left;



		if (old->rb_parent)

		if (rb_parent(old))

		{

			if (old->rb_parent->rb_left == old)

				old->rb_parent->rb_left = node;

			if (rb_parent(old)->rb_left == old)

				rb_parent(old)->rb_left = node;

			else

				old->rb_parent->rb_right = node;

				rb_parent(old)->rb_right = node;

		} else

			root->rb_node = node;



		old->rb_left->rb_parent = node;

		rb_set_parent(old->rb_left, node);

		if (old->rb_right)

			old->rb_right->rb_parent = node;

			rb_set_parent(old->rb_right, node);

		goto color;

	}



	parent = node->rb_parent;

	color = node->rb_color;

	parent = rb_parent(node);

	color = rb_colour(node);



	if (child)

		child->rb_parent = parent;

		rb_set_parent(child, parent);

	if (parent)

	{

		if (parent->rb_left == node)
@@ -322,6 +320,8 @@ EXPORT_SYMBOL(rb_last); 


struct rb_node *rb_next(struct rb_node *node)

{

	struct rb_node *parent;



	/* If we have a right-hand child, go down and then left as far

	   as we can. */

	if (node->rb_right) {
@@ -337,15 +337,17 @@ struct rb_node *rb_next(struct rb_node *node) 
	   ancestor is a right-hand child of its parent, keep going

	   up. First time it's a left-hand child of its parent, said

	   parent is our 'next' node. */

	while (node->rb_parent && node == node->rb_parent->rb_right)

		node = node->rb_parent;

	while ((parent = rb_parent(node)) && node == parent->rb_right)

		node = parent;



	return node->rb_parent;

	return parent;

}

EXPORT_SYMBOL(rb_next);



struct rb_node *rb_prev(struct rb_node *node)

{

	struct rb_node *parent;



	/* If we have a left-hand child, go down and then right as far

	   as we can. */

	if (node->rb_left) {
@@ -357,17 +359,17 @@ struct rb_node *rb_prev(struct rb_node *node) 


	/* No left-hand children. Go up till we find an ancestor which

	   is a right-hand child of its parent */

	while (node->rb_parent && node == node->rb_parent->rb_left)

		node = node->rb_parent;

	while ((parent = rb_parent(node)) && node == parent->rb_left)

		node = parent;



	return node->rb_parent;

	return parent;

}

EXPORT_SYMBOL(rb_prev);



void rb_replace_node(struct rb_node *victim, struct rb_node *new,

		     struct rb_root *root)

{

	struct rb_node *parent = victim->rb_parent;

	struct rb_node *parent = rb_parent(victim);



	/* Set the surrounding nodes to point to the replacement */

	if (parent) {
@@ -379,9 +381,9 @@ void rb_replace_node(struct rb_node *victim, struct rb_node *new, 
		root->rb_node = new;

	}

	if (victim->rb_left)

		victim->rb_left->rb_parent = new;

		rb_set_parent(victim->rb_left, new);

	if (victim->rb_right)

		victim->rb_right->rb_parent = new;

		rb_set_parent(victim->rb_right, new);



	/* Copy the pointers/colour from the victim to the replacement */

	*new = *victim;