[PATCH 4/4] drm/mm: Remove DRM_MM_SEARCH_BEST

[Michel Dänzer]

From: Michel Dänzer <michel.daenzer at amd.com>

In the words of Daniel Vetter:

«I think SEARCH_BEST is pretty much always a bad idea - it rips apart
allocations from the same execbuf, and usually those get recycled around
the same time. Which means you'll just fragment your mm even more if you
try to find the best hole instead of just picking one and the stuffing
the entire execbuf into it. So imo we might as well just kill it.»

Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---

This patch replaces the previous patches 4 and 5.

Not sure about the function header comment hunk, maybe what it says is
true even with DRM_MM_SEARCH_BELOW?

 drivers/gpu/drm/drm_mm.c             | 36 +++++-------------------------------
 drivers/gpu/drm/ttm/ttm_bo_manager.c |  2 +-
 include/drm/drm_mm.h                 |  3 +--
 3 files changed, 7 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/drm_mm.c b/drivers/gpu/drm/drm_mm.c
index 04a209e..3e0ef8c 100644
--- a/drivers/gpu/drm/drm_mm.c
+++ b/drivers/gpu/drm/drm_mm.c
@@ -409,16 +409,11 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
 						      enum drm_mm_search_flags flags)
 {
 	struct drm_mm_node *entry;
-	struct drm_mm_node *best;
 	unsigned long adj_start;
 	unsigned long adj_end;
-	unsigned long best_size;
 
 	BUG_ON(mm->scanned_blocks);
 
-	best = NULL;
-	best_size = ~0UL;
-
 	__drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
 			       flags & DRM_MM_SEARCH_BELOW) {
 		unsigned long hole_size = adj_end - adj_start;
@@ -429,19 +424,11 @@ static struct drm_mm_node *drm_mm_search_free_generic(const struct drm_mm *mm,
 				continue;
 		}
 
-		if (!check_free_hole(adj_start, adj_end, size, alignment))
-			continue;
-
-		if (!(flags & DRM_MM_SEARCH_BEST))
+		if (check_free_hole(adj_start, adj_end, size, alignment))
 			return entry;
-
-		if (hole_size < best_size) {
-			best = entry;
-			best_size = hole_size;
-		}
 	}
 
-	return best;
+	return NULL;
 }
 
 static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_mm *mm,
@@ -453,16 +440,11 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_
 							enum drm_mm_search_flags flags)
 {
 	struct drm_mm_node *entry;
-	struct drm_mm_node *best;
 	unsigned long adj_start;
 	unsigned long adj_end;
-	unsigned long best_size;
 
 	BUG_ON(mm->scanned_blocks);
 
-	best = NULL;
-	best_size = ~0UL;
-
 	__drm_mm_for_each_hole(entry, mm, adj_start, adj_end,
 			       flags & DRM_MM_SEARCH_BELOW) {
 		unsigned long hole_size = adj_end - adj_start;
@@ -478,19 +460,11 @@ static struct drm_mm_node *drm_mm_search_free_in_range_generic(const struct drm_
 				continue;
 		}
 
-		if (!check_free_hole(adj_start, adj_end, size, alignment))
-			continue;
-
-		if (!(flags & DRM_MM_SEARCH_BEST))
+		if (check_free_hole(adj_start, adj_end, size, alignment))
 			return entry;
-
-		if (hole_size < best_size) {
-			best = entry;
-			best_size = hole_size;
-		}
 	}
 
-	return best;
+	return NULL;
 }
 
 /**
@@ -679,7 +653,7 @@ EXPORT_SYMBOL(drm_mm_scan_add_block);
  * corrupted.
  *
  * When the scan list is empty, the selected memory nodes can be freed. An
- * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BEST will then
+ * immediately following drm_mm_search_free with !DRM_MM_SEARCH_BELOW will then
  * return the just freed block (because its at the top of the free_stack list).
  *
  * Returns:
diff --git a/drivers/gpu/drm/ttm/ttm_bo_manager.c b/drivers/gpu/drm/ttm/ttm_bo_manager.c
index aa0bd05..42c2aa9 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_manager.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_manager.c
@@ -55,7 +55,7 @@ static int ttm_bo_man_get_node(struct ttm_mem_type_manager *man,
 	struct ttm_range_manager *rman = (struct ttm_range_manager *) man->priv;
 	struct drm_mm *mm = &rman->mm;
 	struct drm_mm_node *node = NULL;
-	enum drm_mm_search_flags sflags = DRM_MM_SEARCH_BEST;
+	enum drm_mm_search_flags sflags = DRM_MM_SEARCH_DEFAULT;
 	enum drm_mm_allocator_flags aflags = DRM_MM_CREATE_DEFAULT;
 	unsigned long lpfn;
 	int ret;
diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index a24addf..f38f7a0 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -46,8 +46,7 @@
 
 enum drm_mm_search_flags {
 	DRM_MM_SEARCH_DEFAULT =		0,
-	DRM_MM_SEARCH_BEST =		1 << 0,
-	DRM_MM_SEARCH_BELOW =		1 << 1,
+	DRM_MM_SEARCH_BELOW =		1 << 0,
 };
 
 enum drm_mm_allocator_flags {
-- 
2.1.1