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authorDavid Woodhouse <dwmw2@infradead.org>2006-04-21 13:35:51 +0100
committerDavid Woodhouse <dwmw2@infradead.org>2006-04-21 13:35:51 +0100
commit55a981027fc393c86de2c4e7836c9515088a9a58 (patch)
treedd950b79d9f57ce48b2b2a91262b88eecb5296da
parent[RBTREE] Remove dead code in rb_erase() (diff)
downloadlinux-dev-55a981027fc393c86de2c4e7836c9515088a9a58.tar.xz
linux-dev-55a981027fc393c86de2c4e7836c9515088a9a58.zip
[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: David Woodhouse <dwmw2@infradead.org>
Diffstat (limited to '')
-rw-r--r--include/linux/rbtree.h32
-rw-r--r--lib/rbtree.c178
2 files changed, 109 insertions, 101 deletions
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index ffee81ce7b6f..748be50329d8 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -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;
diff --git a/lib/rbtree.c b/lib/rbtree.c
index 63473e04f18a..4a7173cad149 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -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
+ } 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;