drm_mm: add support for range-restricted fair-lru scans

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

2 files changed, 46 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index a6bfc302ed90..c59515ba7e69 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -392,10 +392,36 @@ void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
         mm->scanned_blocks = 0;
         mm->scan_hit_start = 0;
         mm->scan_hit_size = 0;
+        mm->scan_check_range = 0;
 }
 EXPORT_SYMBOL(drm_mm_init_scan);
 
 /**
+ * Initializa lru scanning.
+ *
+ * This simply sets up the scanning routines with the parameters for the desired
+ * hole. This version is for range-restricted scans.
+ *
+ * Warning: As long as the scan list is non-empty, no other operations than
+ * adding/removing nodes to/from the scan list are allowed.
+ */
+void drm_mm_init_scan_with_range(struct drm_mm *mm, unsigned long size,
+                                 unsigned alignment,
+                                 unsigned long start,
+                                 unsigned long end)
+{
+        mm->scan_alignment = alignment;
+        mm->scan_size = size;
+        mm->scanned_blocks = 0;
+        mm->scan_hit_start = 0;
+        mm->scan_hit_size = 0;
+        mm->scan_start = start;
+        mm->scan_end = end;
+        mm->scan_check_range = 1;
+}
+EXPORT_SYMBOL(drm_mm_init_scan_with_range);
+
+/**
  * Add a node to the scan list that might be freed to make space for the desired
  * hole.
  *
@@ -406,6 +432,8 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)
         struct drm_mm *mm = node->mm;
         struct list_head *prev_free, *next_free;
         struct drm_mm_node *prev_node, *next_node;
+        unsigned long adj_start;
+        unsigned long adj_end;
 
         mm->scanned_blocks++;
 
@@ -452,7 +480,17 @@ int drm_mm_scan_add_block(struct drm_mm_node *node)
         node->free_stack.prev = prev_free;
         node->free_stack.next = next_free;
 
-        if (check_free_hole(node->start, node->start + node->size,
+        if (mm->scan_check_range) {
+                adj_start = node->start < mm->scan_start ?
+                        mm->scan_start : node->start;
+                adj_end = node->start + node->size > mm->scan_end ?
+                        mm->scan_end : node->start + node->size;
+        } else {
+                adj_start = node->start;
+                adj_end = node->start + node->size;
+        }
+
+        if (check_free_hole(adj_start , adj_end,
                             mm->scan_size, mm->scan_alignment)) {
                 mm->scan_hit_start = node->start;
                 mm->scan_hit_size = node->size;
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index bf01531193d5..e39177778601 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -62,11 +62,14 @@ struct drm_mm {
         struct list_head unused_nodes;
         int num_unused;
         spinlock_t unused_lock;
+        unsigned int scan_check_range : 1;
         unsigned scan_alignment;
         unsigned long scan_size;
         unsigned long scan_hit_start;
         unsigned scan_hit_size;
         unsigned scanned_blocks;
+        unsigned long scan_start;
+        unsigned long scan_end;
 };
 
 /*
@@ -145,6 +148,10 @@ static inline struct drm_mm *drm_get_mm(struct drm_mm_node *block)
 
 void drm_mm_init_scan(struct drm_mm *mm, unsigned long size,
                       unsigned alignment);
+void drm_mm_init_scan_with_range(struct drm_mm *mm, unsigned long size,
+                                 unsigned alignment,
+                                 unsigned long start,
+                                 unsigned long end);
 int drm_mm_scan_add_block(struct drm_mm_node *node);
 int drm_mm_scan_remove_block(struct drm_mm_node *node);