Skipping just one branch of the tree is not the most
effective approach.
Instead use a macro to define the traversal functions and
sort out both branch sides.
This improves the performance of the unit tests by
a factor of more than 4.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/drm_mm.c | 106 +++++++++++++--------------------------
1 file changed, 34 insertions(+), 72 deletions(-)
diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 177a5df0fe95..a4a04d246135 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -325,6 +325,11 @@ static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
return best;
}
+static bool usable_hole_addr(struct rb_node *rb, u64 size)
+{
+ return rb && rb_hole_addr_to_node(rb)->subtree_max_hole >= size;
+}
+
static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
{
struct rb_node *rb = mm->holes_addr.rb_node;
@@ -333,7 +338,7 @@ static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
while (rb) {
u64 hole_start;
- if (rb_hole_addr_to_node(rb)->subtree_max_hole < size)
+ if (!usable_hole_addr(rb, size))
break;
node = rb_hole_addr_to_node(rb);
@@ -374,82 +379,39 @@ first_hole(struct drm_mm *mm,
}
/**
- * next_hole_high_addr - returns next hole for a DRM_MM_INSERT_HIGH mode request
- * @entry: previously selected drm_mm_node
- * @size: size of the a hole needed for the request
- *
- * This function will verify whether left subtree of @entry has hole big enough
- * to fit the requtested size. If so, it will return previous node of @entry or
- * else it will return parent node of @entry
+ * DECLARE_NEXT_HOLE_ADDR - macro to declare next hole functions
+ * @name: name of function to declare
+ * @first: first rb member to traverse (either rb_left or rb_right).
+ * @last: last rb member to traverse (either rb_right or rb_left).
*
- * It will also skip the complete left subtree if subtree_max_hole of that
- * subtree is same as the subtree_max_hole of the @entry.
- *
- * Returns:
- * previous node of @entry if left subtree of @entry can serve the request or
- * else return parent of @entry
+ * This macro declares a function to return the next hole of the addr rb tree.
+ * While traversing the tree we take the searched size into account and only
+ * visit branches with potential big enough holes.
*/
-static struct drm_mm_node *
-next_hole_high_addr(struct drm_mm_node *entry, u64 size)
-{
- struct rb_node *rb_node, *left_rb_node, *parent_rb_node;
- struct drm_mm_node *left_node;
-
- if (!entry)
- return NULL;
- rb_node = &entry->rb_hole_addr;
- if (rb_node->rb_left) {
- left_rb_node = rb_node->rb_left;
- parent_rb_node = rb_parent(rb_node);
- left_node = rb_entry(left_rb_node,
- struct drm_mm_node, rb_hole_addr);
- if (left_node->subtree_max_hole < size &&
- parent_rb_node && parent_rb_node->rb_left != rb_node)
- return rb_hole_addr_to_node(parent_rb_node);
- }
-
- return rb_hole_addr_to_node(rb_prev(rb_node));
+#define DECLARE_NEXT_HOLE_ADDR(name, first, last) \
+static struct drm_mm_node *name(struct drm_mm_node *entry, u64 size) \
+{ \
+ struct rb_node *parent, *node = &entry->rb_hole_addr; \
+ \
+ if (!entry || RB_EMPTY_NODE(node)) \
+ return NULL; \
+ \
+ if (usable_hole_addr(node->first, size)) { \
+ node = node->first; \
+ while (usable_hole_addr(node->last, size)) \
+ node = node->last; \
+ return rb_hole_addr_to_node(node); \
+ } \
+ \
+ while ((parent = rb_parent(node)) && node == parent->first) \
+ node = parent; \
+ \
+ return rb_hole_addr_to_node(parent); \
}
-/**
- * next_hole_low_addr - returns next hole for a DRM_MM_INSERT_LOW mode request
- * @entry: previously selected drm_mm_node
- * @size: size of the a hole needed for the request
- *
- * This function will verify whether right subtree of @entry has hole big enough
- * to fit the requtested size. If so, it will return next node of @entry or
- * else it will return parent node of @entry
- *
- * It will also skip the complete right subtree if subtree_max_hole of that
- * subtree is same as the subtree_max_hole of the @entry.
- *
- * Returns:
- * next node of @entry if right subtree of @entry can serve the request or
- * else return parent of @entry
- */
-static struct drm_mm_node *
-next_hole_low_addr(struct drm_mm_node *entry, u64 size)
-{
- struct rb_node *rb_node, *right_rb_node, *parent_rb_node;
- struct drm_mm_node *right_node;
-
- if (!entry)
- return NULL;
-
- rb_node = &entry->rb_hole_addr;
- if (rb_node->rb_right) {
- right_rb_node = rb_node->rb_right;
- parent_rb_node = rb_parent(rb_node);
- right_node = rb_entry(right_rb_node,
- struct drm_mm_node, rb_hole_addr);
- if (right_node->subtree_max_hole < size &&
- parent_rb_node && parent_rb_node->rb_right != rb_node)
- return rb_hole_addr_to_node(parent_rb_node);
- }
-
- return rb_hole_addr_to_node(rb_next(rb_node));
-}
+DECLARE_NEXT_HOLE_ADDR(next_hole_high_addr, rb_left, rb_right)
+DECLARE_NEXT_HOLE_ADDR(next_hole_low_addr, rb_right, rb_left)
static struct drm_mm_node *
next_hole(struct drm_mm *mm,
--
2.17.1
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