drm/ttm: Rework validation & memory space allocation (V3)

This change allow driver to pass sorted memory placement,
from most prefered placement to least prefered placement.
In order to avoid long function prototype a structure is
used to gather memory placement informations such as range
restriction (if you need a buffer to be in given range).
Range restriction is determined by fpfn & lpfn which are
the first page and last page number btw which allocation
can happen. If those fields are set to 0 ttm will assume
buffer can be put anywhere in the address space (thus it
avoids putting a burden on the driver to always properly
set those fields).

This patch also factor few functions like evicting first
entry of lru list or getting a memory space. This avoid
code duplication.

V2: Change API to use placement flags and array instead
    of packing placement order into a quadword.
V3: Make sure we set the appropriate mem.placement flag
    when validating or allocation memory space.

[Pending Thomas Hellstrom further review but okay
from preliminary review so far].
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

include/drm/ttm/ttm_bo_api.h

@@ -44,6 +44,29 @@ struct ttm_bo_device;
 
 struct drm_mm_node;
 
+
+/**
+ * struct ttm_placement
+ *
+ * @fpfn:		first valid page frame number to put the object
+ * @lpfn:		last valid page frame number to put the object
+ * @num_placement:	number of prefered placements
+ * @placement:		prefered placements
+ * @num_busy_placement:	number of prefered placements when need to evict buffer
+ * @busy_placement:	prefered placements when need to evict buffer
+ *
+ * Structure indicating the placement you request for an object.
+ */
+struct ttm_placement {
+	unsigned	fpfn;
+	unsigned	lpfn;
+	unsigned	num_placement;
+	const uint32_t	*placement;
+	unsigned	num_busy_placement;
+	const uint32_t	*busy_placement;
+};
+
+
 /**
  * struct ttm_mem_reg
  *
@@ -109,10 +132,6 @@ struct ttm_tt;
  * the object is destroyed.
  * @event_queue: Queue for processes waiting on buffer object status change.
  * @lock: spinlock protecting mostly synchronization members.
- * @proposed_placement: Proposed placement for the buffer. Changed only by the
- * creator prior to validation as opposed to bo->mem.proposed_flags which is
- * changed by the implementation prior to a buffer move if it wants to outsmart
- * the buffer creator / user. This latter happens, for example, at eviction.
  * @mem: structure describing current placement.
  * @persistant_swap_storage: Usually the swap storage is deleted for buffers
  * pinned in physical memory. If this behaviour is not desired, this member
@@ -177,7 +196,6 @@ struct ttm_buffer_object {
 	 * Members protected by the bo::reserved lock.
 	 */
 
-	uint32_t proposed_placement;
 	struct ttm_mem_reg mem;
 	struct file *persistant_swap_storage;
 	struct ttm_tt *ttm;
@@ -293,21 +311,22 @@ extern int ttm_bo_wait(struct ttm_buffer_object *bo, bool lazy,
  * ttm_buffer_object_validate
  *
  * @bo: The buffer object.
- * @proposed_placement: Proposed_placement for the buffer object.
+ * @placement: Proposed placement for the buffer object.
  * @interruptible: Sleep interruptible if sleeping.
  * @no_wait: Return immediately if the buffer is busy.
  *
  * Changes placement and caching policy of the buffer object
- * according to bo::proposed_flags.
+ * according proposed placement.
  * Returns
- * -EINVAL on invalid proposed_flags.
+ * -EINVAL on invalid proposed placement.
  * -ENOMEM on out-of-memory condition.
  * -EBUSY if no_wait is true and buffer busy.
  * -ERESTART if interrupted by a signal.
  */
 extern int ttm_buffer_object_validate(struct ttm_buffer_object *bo,
-				      uint32_t proposed_placement,
-				      bool interruptible, bool no_wait);
+					struct ttm_placement *placement,
+					bool interruptible, bool no_wait);
+
 /**
  * ttm_bo_unref
  *
@@ -445,7 +464,6 @@ extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
  *
  * @bdev: Pointer to a ttm_bo_device struct.
  * @mem_type: The memory type.
- * @p_offset: offset for managed area in pages.
  * @p_size: size managed area in pages.
  *
  * Initialize a manager for a given memory type.
@@ -458,7 +476,7 @@ extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
  */
 
 extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
-			  unsigned long p_offset, unsigned long p_size);
+				unsigned long p_size);
 /**
  * ttm_bo_clean_mm
  *

include/drm/ttm/ttm_bo_driver.h

@@ -242,12 +242,6 @@ struct ttm_mem_type_manager {
 /**
  * struct ttm_bo_driver
  *
- * @mem_type_prio: Priority array of memory types to place a buffer object in
- * if it fits without evicting buffers from any of these memory types.
- * @mem_busy_prio: Priority array of memory types to place a buffer object in
- * if it needs to evict buffers to make room.
- * @num_mem_type_prio: Number of elements in the @mem_type_prio array.
- * @num_mem_busy_prio: Number of elements in the @num_mem_busy_prio array.
  * @create_ttm_backend_entry: Callback to create a struct ttm_backend.
  * @invalidate_caches: Callback to invalidate read caches when a buffer object
  * has been evicted.
@@ -265,11 +259,6 @@ struct ttm_mem_type_manager {
  */
 
 struct ttm_bo_driver {
-	const uint32_t *mem_type_prio;
-	const uint32_t *mem_busy_prio;
-	uint32_t num_mem_type_prio;
-	uint32_t num_mem_busy_prio;
-
 	/**
 	 * struct ttm_bo_driver member create_ttm_backend_entry
 	 *
@@ -306,7 +295,8 @@ struct ttm_bo_driver {
 	 * finished, they'll end up in bo->mem.flags
 	 */
 
-	 uint32_t(*evict_flags) (struct ttm_buffer_object *bo);
+	 void(*evict_flags) (struct ttm_buffer_object *bo,
+				struct ttm_placement *placement);
 	/**
 	 * struct ttm_bo_driver member move:
 	 *
@@ -651,9 +641,9 @@ extern bool ttm_mem_reg_is_pci(struct ttm_bo_device *bdev,
  * -ERESTART: An interruptible sleep was interrupted by a signal.
  */
 extern int ttm_bo_mem_space(struct ttm_buffer_object *bo,
-			    uint32_t proposed_placement,
-			    struct ttm_mem_reg *mem,
-			    bool interruptible, bool no_wait);
+				struct ttm_placement *placement,
+				struct ttm_mem_reg *mem,
+				bool interruptible, bool no_wait);
 /**
  * ttm_bo_wait_for_cpu
  *