drm: mm: track free areas implicitly
The idea is to track free holes implicitly by marking the allocation
immediatly preceeding a hole.
To avoid an ugly corner case add a dummy head_node to struct drm_mm
to track the hole that spans to complete allocation area when the
memory manager is empty.
To guarantee that there's always a preceeding/following node (that might
be marked as hole_follows == 1), move the mm->node_list list_head to the
head_node.
The main allocator and fair-lru scan code actually becomes simpler.
Only the debug code slightly suffers because free areas are no longer
explicit.
Also add drm_mm_for_each_node (which will be much more useful when
struct drm_mm_node is embeddable).
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index 0d79146..34fa36f 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -42,23 +42,24 @@
#endif
struct drm_mm_node {
- struct list_head free_stack;
struct list_head node_list;
- unsigned free : 1;
+ struct list_head hole_stack;
+ unsigned hole_follows : 1;
unsigned scanned_block : 1;
unsigned scanned_prev_free : 1;
unsigned scanned_next_free : 1;
+ unsigned scanned_preceeds_hole : 1;
unsigned long start;
unsigned long size;
struct drm_mm *mm;
};
struct drm_mm {
- /* List of free memory blocks, most recently freed ordered. */
- struct list_head free_stack;
- /* List of all memory nodes, ordered according to the (increasing) start
- * address of the memory node. */
- struct list_head node_list;
+ /* List of all memory nodes that immediatly preceed a free hole. */
+ struct list_head hole_stack;
+ /* head_node.node_list is the list of all memory nodes, ordered
+ * according to the (increasing) start address of the memory node. */
+ struct drm_mm_node head_node;
struct list_head unused_nodes;
int num_unused;
spinlock_t unused_lock;
@@ -74,9 +75,11 @@
static inline bool drm_mm_initialized(struct drm_mm *mm)
{
- return mm->free_stack.next;
+ return mm->hole_stack.next;
}
-
+#define drm_mm_for_each_node(entry, mm) list_for_each_entry(entry, \
+ &(mm)->head_node.node_list, \
+ node_list);
/*
* Basic range manager support (drm_mm.c)
*/