drm/i915: Extract reserving space in the GTT to a helper

Extract drm_mm_reserve_node + calling i915_gem_evict_for_node into its
own routine so that it can be shared rather than duplicated.

v2: Kerneldoc

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: igvt-g-dev@lists.01.org
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170111112312.31493-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_drv.h

@@ -3469,8 +3469,9 @@ int __must_check i915_gem_evict_something(struct i915_address_space *vm,
 					  unsigned cache_level,
 					  u64 start, u64 end,
 					  unsigned flags);
-int __must_check i915_gem_evict_for_vma(struct i915_vma *vma,
-					unsigned int flags);
+int __must_check i915_gem_evict_for_node(struct i915_address_space *vm,
+					 struct drm_mm_node *node,
+					 unsigned int flags);
 int i915_gem_evict_vm(struct i915_address_space *vm, bool do_idle);
 
 /* belongs in i915_gem_gtt.h */

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -231,45 +231,48 @@ i915_gem_evict_something(struct i915_address_space *vm,
 
 /**
  * i915_gem_evict_for_vma - Evict vmas to make room for binding a new one
- * @target: address space and range to evict for
+ * @vm: address space to evict from
+ * @target: range (and color) to evict for
  * @flags: additional flags to control the eviction algorithm
  *
  * This function will try to evict vmas that overlap the target node.
  *
  * To clarify: This is for freeing up virtual address space, not for freeing
  * memory in e.g. the shrinker.
  */
-int i915_gem_evict_for_vma(struct i915_vma *target, unsigned int flags)
+int i915_gem_evict_for_node(struct i915_address_space *vm,
+			    struct drm_mm_node *target,
+			    unsigned int flags)
 {
 	LIST_HEAD(eviction_list);
 	struct drm_mm_node *node;
-	u64 start = target->node.start;
-	u64 end = start + target->node.size;
+	u64 start = target->start;
+	u64 end = start + target->size;
 	struct i915_vma *vma, *next;
 	bool check_color;
 	int ret = 0;
 
-	lockdep_assert_held(&target->vm->i915->drm.struct_mutex);
-	trace_i915_gem_evict_vma(target, flags);
+	lockdep_assert_held(&vm->i915->drm.struct_mutex);
+	trace_i915_gem_evict_node(vm, target, flags);
 
 	/* Retire before we search the active list. Although we have
 	 * reasonable accuracy in our retirement lists, we may have
 	 * a stray pin (preventing eviction) that can only be resolved by
 	 * retiring.
 	 */
 	if (!(flags & PIN_NONBLOCK))
-		i915_gem_retire_requests(target->vm->i915);
+		i915_gem_retire_requests(vm->i915);
 
-	check_color = target->vm->mm.color_adjust;
+	check_color = vm->mm.color_adjust;
 	if (check_color) {
 		/* Expand search to cover neighbouring guard pages (or lack!) */
-		if (start > target->vm->start)
+		if (start > vm->start)
 			start -= I915_GTT_PAGE_SIZE;
-		if (end < target->vm->start + target->vm->total)
+		if (end < vm->start + vm->total)
 			end += I915_GTT_PAGE_SIZE;
 	}
 
-	drm_mm_for_each_node_in_range(node, &target->vm->mm, start, end) {
+	drm_mm_for_each_node_in_range(node, &vm->mm, start, end) {
 		/* If we find any non-objects (!vma), we cannot evict them */
 		if (node->color == I915_COLOR_UNEVICTABLE) {
 			ret = -ENOSPC;
@@ -285,12 +288,12 @@ int i915_gem_evict_for_vma(struct i915_vma *target, unsigned int flags)
 		 * those as well to make room for our guard pages.
 		 */
 		if (check_color) {
-			if (vma->node.start + vma->node.size == target->node.start) {
-				if (vma->node.color == target->node.color)
+			if (vma->node.start + vma->node.size == node->start) {
+				if (vma->node.color == node->color)
 					continue;
 			}
-			if (vma->node.start == target->node.start + target->node.size) {
-				if (vma->node.color == target->node.color)
+			if (vma->node.start == node->start + node->size) {
+				if (vma->node.color == node->color)
 					continue;
 			}
 		}

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -3554,6 +3554,58 @@ i915_get_ggtt_vma_pages(struct i915_vma *vma)
 	return ret;
 }
 
+/**
+ * i915_gem_gtt_reserve - reserve a node in an address_space (GTT)
+ * @vm - the &struct i915_address_space
+ * @node - the &struct drm_mm_node (typically i915_vma.mode)
+ * @size - how much space to allocate inside the GTT,
+ *         must be #I915_GTT_PAGE_SIZE aligned
+ * @offset - where to insert inside the GTT,
+ *           must be #I915_GTT_MIN_ALIGNMENT aligned, and the node
+ *           (@offset + @size) must fit within the address space
+ * @color - color to apply to node, if this node is not from a VMA,
+ *          color must be #I915_COLOR_UNEVICTABLE
+ * @flags - control search and eviction behaviour
+ *
+ * i915_gem_gtt_reserve() tries to insert the @node at the exact @offset inside
+ * the address space (using @size and @color). If the @node does not fit, it
+ * tries to evict any overlapping nodes from the GTT, including any
+ * neighbouring nodes if the colors do not match (to ensure guard pages between
+ * differing domains). See i915_gem_evict_for_node() for the gory details
+ * on the eviction algorithm. #PIN_NONBLOCK may used to prevent waiting on
+ * evicting active overlapping objects, and any overlapping node that is pinned
+ * or marked as unevictable will also result in failure.
+ *
+ * Returns: 0 on success, -ENOSPC if no suitable hole is found, -EINTR if
+ * asked to wait for eviction and interrupted.
+ */
+int i915_gem_gtt_reserve(struct i915_address_space *vm,
+			 struct drm_mm_node *node,
+			 u64 size, u64 offset, unsigned long color,
+			 unsigned int flags)
+{
+	int err;
+
+	GEM_BUG_ON(!size);
+	GEM_BUG_ON(!IS_ALIGNED(size, I915_GTT_PAGE_SIZE));
+	GEM_BUG_ON(!IS_ALIGNED(offset, I915_GTT_MIN_ALIGNMENT));
+	GEM_BUG_ON(range_overflows(offset, size, vm->total));
+
+	node->size = size;
+	node->start = offset;
+	node->color = color;
+
+	err = drm_mm_reserve_node(&vm->mm, node);
+	if (err != -ENOSPC)
+		return err;
+
+	err = i915_gem_evict_for_node(vm, node, flags);
+	if (err == 0)
+		err = drm_mm_reserve_node(&vm->mm, node);
+
+	return err;
+}
+
 /**
  * i915_gem_gtt_insert - insert a node into an address_space (GTT)
  * @vm - the &struct i915_address_space

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -532,6 +532,11 @@ int __must_check i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj,
 void i915_gem_gtt_finish_pages(struct drm_i915_gem_object *obj,
 			       struct sg_table *pages);
 
+int i915_gem_gtt_reserve(struct i915_address_space *vm,
+			 struct drm_mm_node *node,
+			 u64 size, u64 offset, unsigned long color,
+			 unsigned int flags);
+
 int i915_gem_gtt_insert(struct i915_address_space *vm,
 			struct drm_mm_node *node,
 			u64 size, u64 alignment, unsigned long color,

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -694,10 +694,9 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_i915_private *dev_priv
 	 * setting up the GTT space. The actual reservation will occur
 	 * later.
 	 */
-	vma->node.start = gtt_offset;
-	vma->node.size = size;
-
-	ret = drm_mm_reserve_node(&ggtt->base.mm, &vma->node);
+	ret = i915_gem_gtt_reserve(&ggtt->base, &vma->node,
+				   size, gtt_offset, obj->cache_level,
+				   0);
 	if (ret) {
 		DRM_DEBUG_KMS("failed to allocate stolen GTT space\n");
 		goto err_pages;

drivers/gpu/drm/i915/i915_trace.h

@@ -450,9 +450,9 @@ TRACE_EVENT(i915_gem_evict_vm,
 	    TP_printk("dev=%d, vm=%p", __entry->dev, __entry->vm)
 );
 
-TRACE_EVENT(i915_gem_evict_vma,
-	    TP_PROTO(struct i915_vma *vma, unsigned int flags),
-	    TP_ARGS(vma, flags),
+TRACE_EVENT(i915_gem_evict_node,
+	    TP_PROTO(struct i915_address_space *vm, struct drm_mm_node *node, unsigned int flags),
+	    TP_ARGS(vm, node, flags),
 
 	    TP_STRUCT__entry(
 			     __field(u32, dev)
@@ -464,11 +464,11 @@ TRACE_EVENT(i915_gem_evict_vma,
 			    ),
 
 	    TP_fast_assign(
-			   __entry->dev = vma->vm->i915->drm.primary->index;
-			   __entry->vm = vma->vm;
-			   __entry->start = vma->node.start;
-			   __entry->size = vma->node.size;
-			   __entry->color = vma->node.color;
+			   __entry->dev = vm->i915->drm.primary->index;
+			   __entry->vm = vm;
+			   __entry->start = node->start;
+			   __entry->size = node->size;
+			   __entry->color = node->color;
 			   __entry->flags = flags;
 			  ),
 

drivers/gpu/drm/i915/i915_vgpu.c

@@ -116,22 +116,20 @@ void intel_vgt_deballoon(struct drm_i915_private *dev_priv)
 	memset(&bl_info, 0, sizeof(bl_info));
 }
 
-static int vgt_balloon_space(struct drm_mm *mm,
+static int vgt_balloon_space(struct i915_ggtt *ggtt,
 			     struct drm_mm_node *node,
 			     unsigned long start, unsigned long end)
 {
 	unsigned long size = end - start;
 
-	if (start == end)
+	if (start <= end)
 		return -EINVAL;
 
 	DRM_INFO("balloon space: range [ 0x%lx - 0x%lx ] %lu KiB.\n",
 		 start, end, size / 1024);
-
-	node->start = start;
-	node->size = size;
-
-	return drm_mm_reserve_node(mm, node);
+	return i915_gem_gtt_reserve(&ggtt->base, node,
+				    size, start, I915_COLOR_UNEVICTABLE,
+				    0);
 }
 
 /**
@@ -214,10 +212,8 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 
 	/* Unmappable graphic memory ballooning */
 	if (unmappable_base > ggtt->mappable_end) {
-		ret = vgt_balloon_space(&ggtt->base.mm,
-					&bl_info.space[2],
-					ggtt->mappable_end,
-					unmappable_base);
+		ret = vgt_balloon_space(ggtt, &bl_info.space[2],
+					ggtt->mappable_end, unmappable_base);
 
 		if (ret)
 			goto err;
@@ -228,29 +224,24 @@ int intel_vgt_balloon(struct drm_i915_private *dev_priv)
 	 * because it is reserved to the guard page.
 	 */
 	if (unmappable_end < ggtt_end - PAGE_SIZE) {
-		ret = vgt_balloon_space(&ggtt->base.mm,
-					&bl_info.space[3],
-					unmappable_end,
-					ggtt_end - PAGE_SIZE);
+		ret = vgt_balloon_space(ggtt, &bl_info.space[3],
+					unmappable_end, ggtt_end - PAGE_SIZE);
 		if (ret)
 			goto err;
 	}
 
 	/* Mappable graphic memory ballooning */
 	if (mappable_base > ggtt->base.start) {
-		ret = vgt_balloon_space(&ggtt->base.mm,
-					&bl_info.space[0],
+		ret = vgt_balloon_space(ggtt, &bl_info.space[0],
 					ggtt->base.start, mappable_base);
 
 		if (ret)
 			goto err;
 	}
 
 	if (mappable_end < ggtt->mappable_end) {
-		ret = vgt_balloon_space(&ggtt->base.mm,
-					&bl_info.space[1],
-					mappable_end,
-					ggtt->mappable_end);
+		ret = vgt_balloon_space(ggtt, &bl_info.space[1],
+					mappable_end, ggtt->mappable_end);
 
 		if (ret)
 			goto err;

drivers/gpu/drm/i915/i915_vma.c

@@ -419,17 +419,11 @@ i915_vma_insert(struct i915_vma *vma, u64 size, u64 alignment, u64 flags)
 			goto err_unpin;
 		}
 
-		vma->node.start = offset;
-		vma->node.size = size;
-		vma->node.color = obj->cache_level;
-		ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
-		if (ret) {
-			ret = i915_gem_evict_for_vma(vma, flags);
-			if (ret == 0)
-				ret = drm_mm_reserve_node(&vma->vm->mm, &vma->node);
-			if (ret)
-				goto err_unpin;
-		}
+		ret = i915_gem_gtt_reserve(vma->vm, &vma->node,
+					   size, offset, obj->cache_level,
+					   flags);
+		if (ret)
+			goto err_unpin;
 	} else {
 		ret = i915_gem_gtt_insert(vma->vm, &vma->node,
 					  size, alignment, obj->cache_level,