Re: [PATCH 6/6] rbtree: remove prior augmented rbtreeimplementation

From: Michel Lespinasse
Date: Mon Jul 23 2012 - 21:55:07 EST


convert arch/x86/mm/pat_rbtree.c to the proposed augmented rbtree api
and remove the old augmented rbtree implementation.

Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
---
arch/x86/mm/pat_rbtree.c | 63 ++++++++++++++++++++++++++++------------
include/linux/rbtree.h | 8 -----
lib/rbtree.c | 71 ----------------------------------------------
lib/rbtree_test.c | 11 ++-----
4 files changed, 47 insertions(+), 106 deletions(-)

diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
index 8acaddd..5b8c8b2 100644
--- a/arch/x86/mm/pat_rbtree.c
+++ b/arch/x86/mm/pat_rbtree.c
@@ -13,6 +13,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/rbtree.h>
+#include <linux/rbtree_internal.h>
#include <linux/sched.h>
#include <linux/gfp.h>

@@ -54,27 +55,51 @@ static u64 get_subtree_max_end(struct rb_node *node)
return ret;
}

-/* Update 'subtree_max_end' for a node, based on node and its children */
-static void memtype_rb_augment_cb(struct rb_node *node, void *__unused)
+static u64 compute_subtree_max_end(struct memtype *data)
{
- struct memtype *data;
- u64 max_end, child_max_end;
-
- if (!node)
- return;
-
- data = container_of(node, struct memtype, rb);
- max_end = data->end;
+ u64 max_end = data->end, child_max_end;

- child_max_end = get_subtree_max_end(node->rb_right);
+ child_max_end = get_subtree_max_end(data->rb.rb_right);
if (child_max_end > max_end)
max_end = child_max_end;

- child_max_end = get_subtree_max_end(node->rb_left);
+ child_max_end = get_subtree_max_end(data->rb.rb_left);
if (child_max_end > max_end)
max_end = child_max_end;

- data->subtree_max_end = max_end;
+ return max_end;
+}
+
+/* Update 'subtree_max_end' after tree rotation. old and new are the
+ * former and current subtree roots */
+static void memtype_rb_rotate_cb(struct rb_node *old, struct rb_node *new)
+{
+ struct memtype *old_data = container_of(old, struct memtype, rb);
+ struct memtype *new_data = container_of(new, struct memtype, rb);
+
+ new_data->subtree_max_end = old_data->subtree_max_end;
+ old_data->subtree_max_end = compute_subtree_max_end(old_data);
+}
+
+static void memtype_rb_copy_cb(struct rb_node *old, struct rb_node *new)
+{
+ struct memtype *old_data = container_of(old, struct memtype, rb);
+ struct memtype *new_data = container_of(new, struct memtype, rb);
+
+ new_data->subtree_max_end = old_data->subtree_max_end;
+}
+
+/* Update 'subtree_max_end' for node and its parents */
+static void memtype_rb_propagate_cb(struct rb_node *node, struct rb_node *stop)
+{
+ while (node != stop) {
+ struct memtype *data = container_of(node, struct memtype, rb);
+ u64 subtree_max_end = compute_subtree_max_end(data);
+ if (data->subtree_max_end == subtree_max_end)
+ break;
+ data->subtree_max_end = subtree_max_end;
+ node = rb_parent(&data->rb);
+ }
}

/* Find the first (lowest start addr) overlapping range from rb tree */
@@ -179,15 +204,17 @@ static void memtype_rb_insert(struct rb_root *root, struct memtype *newdata)
struct memtype *data = container_of(*node, struct memtype, rb);

parent = *node;
+ if (data->subtree_max_end < newdata->end)
+ data->subtree_max_end = newdata->end;
if (newdata->start <= data->start)
node = &((*node)->rb_left);
else if (newdata->start > data->start)
node = &((*node)->rb_right);
}

+ newdata->subtree_max_end = newdata->end;
rb_link_node(&newdata->rb, parent, node);
- rb_insert_color(&newdata->rb, root);
- rb_augment_insert(&newdata->rb, memtype_rb_augment_cb, NULL);
+ rb_insert_augmented(&newdata->rb, root, memtype_rb_rotate_cb);
}

int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
@@ -209,16 +236,14 @@ int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)

struct memtype *rbt_memtype_erase(u64 start, u64 end)
{
- struct rb_node *deepest;
struct memtype *data;

data = memtype_rb_exact_match(&memtype_rbroot, start, end);
if (!data)
goto out;

- deepest = rb_augment_erase_begin(&data->rb);
- rb_erase(&data->rb, &memtype_rbroot);
- rb_augment_erase_end(deepest, memtype_rb_augment_cb, NULL);
+ rb_erase_augmented(&data->rb, &memtype_rbroot, memtype_rb_copy_cb,
+ memtype_rb_propagate_cb, memtype_rb_rotate_cb);
out:
return data;
}
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index bf836a2..487f00b 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -61,14 +61,6 @@ struct rb_root {
extern void rb_insert_color(struct rb_node *, struct rb_root *);
extern void rb_erase(struct rb_node *, struct rb_root *);

-typedef void (*rb_augment_f)(struct rb_node *node, void *data);
-
-extern void rb_augment_insert(struct rb_node *node,
- rb_augment_f func, void *data);
-extern struct rb_node *rb_augment_erase_begin(struct rb_node *node);
-extern void rb_augment_erase_end(struct rb_node *node,
- rb_augment_f func, void *data);
-
/* Find logical next and previous nodes in a tree */
extern struct rb_node *rb_next(const struct rb_node *);
extern struct rb_node *rb_prev(const struct rb_node *);
diff --git a/lib/rbtree.c b/lib/rbtree.c
index 90349ec..62080ce 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -366,77 +366,6 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
}
EXPORT_SYMBOL(rb_erase);

-static void rb_augment_path(struct rb_node *node, rb_augment_f func, void *data)
-{
- struct rb_node *parent;
-
-up:
- func(node, data);
- parent = rb_parent(node);
- if (!parent)
- return;
-
- if (node == parent->rb_left && parent->rb_right)
- func(parent->rb_right, data);
- else if (parent->rb_left)
- func(parent->rb_left, data);
-
- node = parent;
- goto up;
-}
-
-/*
- * after inserting @node into the tree, update the tree to account for
- * both the new entry and any damage done by rebalance
- */
-void rb_augment_insert(struct rb_node *node, rb_augment_f func, void *data)
-{
- if (node->rb_left)
- node = node->rb_left;
- else if (node->rb_right)
- node = node->rb_right;
-
- rb_augment_path(node, func, data);
-}
-EXPORT_SYMBOL(rb_augment_insert);
-
-/*
- * before removing the node, find the deepest node on the rebalance path
- * that will still be there after @node gets removed
- */
-struct rb_node *rb_augment_erase_begin(struct rb_node *node)
-{
- struct rb_node *deepest;
-
- if (!node->rb_right && !node->rb_left)
- deepest = rb_parent(node);
- else if (!node->rb_right)
- deepest = node->rb_left;
- else if (!node->rb_left)
- deepest = node->rb_right;
- else {
- deepest = rb_next(node);
- if (deepest->rb_right)
- deepest = deepest->rb_right;
- else if (rb_parent(deepest) != node)
- deepest = rb_parent(deepest);
- }
-
- return deepest;
-}
-EXPORT_SYMBOL(rb_augment_erase_begin);
-
-/*
- * after removal, update the tree to account for the removed entry
- * and any rebalance damage.
- */
-void rb_augment_erase_end(struct rb_node *node, rb_augment_f func, void *data)
-{
- if (node)
- rb_augment_path(node, func, data);
-}
-EXPORT_SYMBOL(rb_augment_erase_end);
-
/*
* This function returns the first node (in sort order) of the tree.
*/
diff --git a/lib/rbtree_test.c b/lib/rbtree_test.c
index 278dbfc..140e173 100644
--- a/lib/rbtree_test.c
+++ b/lib/rbtree_test.c
@@ -129,16 +129,11 @@ static void init(void)
}
}

-static bool is_red(struct rb_node *rb)
-{
- return !(rb->__rb_parent_color & 1);
-}
-
static int black_path_count(struct rb_node *rb)
{
int count;
for (count = 0; rb; rb = rb_parent(rb))
- count += !is_red(rb);
+ count += rb_is_black(rb);
return count;
}

@@ -152,8 +147,8 @@ static void check(int nr_nodes)
for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
struct test_node *node = rb_entry(rb, struct test_node, rb);
WARN_ON_ONCE(node->key < prev_key);
- WARN_ON_ONCE(is_red(rb) &&
- (!rb_parent(rb) || is_red(rb_parent(rb))));
+ WARN_ON_ONCE(rb_is_red(rb) &&
+ (!rb_parent(rb) || rb_is_red(rb_parent(rb))));
if (!count)
blacks = black_path_count(rb);
else
--
1.7.7.3

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