intel: Always allocate miptrees from level 0, not tObj->BaseLevel.

BaseLevel/MaxLevel are mostly used for two things: clamping texture
access for FBO rendering, and limiting the used mipmap levels when
incrementally loading textures.  By restricting our mipmap trees to
just the current BaseLevel/MaxLevel, we caused reallocation thrashing
in the common case, for a theoretical win if someone really did want
just levels 2..4 or whatever of their texture object.

Bug #30366

1 files changed, 35 insertions, 90 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_tex_image.c b/src/mesa/drivers/dri/intel/intel_tex_image.c
index 918740a773..e0d4ca762f 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_image.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_image.c
@@ -44,24 +44,12 @@ logbase2(int n)
    return log2;
 }
 
-
-/* Otherwise, store it in memory if (Border != 0) or (any dimension ==
- * 1).
- *    
- * Otherwise, if max_level >= level >= min_level, create tree with
- * space for textures from min_level down to max_level.
- *
- * Otherwise, create tree with space for textures from (level
- * 0)..(1x1).  Consider pruning this tree at a validation if the
- * saving is worth it.
- */
-static void
-guess_and_alloc_mipmap_tree(struct intel_context *intel,
-                            struct intel_texture_object *intelObj,
-                            struct intel_texture_image *intelImage,
-			    GLboolean expect_accelerated_upload)
+struct intel_mipmap_tree *
+intel_miptree_create_for_teximage(struct intel_context *intel,
+				  struct intel_texture_object *intelObj,
+				  struct intel_texture_image *intelImage,
+				  GLboolean expect_accelerated_upload)
 {
-   GLuint firstLevel;
    GLuint lastLevel;
    GLuint width = intelImage->base.Width;
    GLuint height = intelImage->base.Height;
@@ -72,28 +60,11 @@ guess_and_alloc_mipmap_tree(struct intel_context *intel,
    DBG("%s\n", __FUNCTION__);
 
    if (intelImage->base.Border)
-      return;
-
-   if (intelImage->level > intelObj->base.BaseLevel &&
-       (intelImage->base.Width == 1 ||
-        (intelObj->base.Target != GL_TEXTURE_1D &&
-         intelImage->base.Height == 1) ||
-        (intelObj->base.Target == GL_TEXTURE_3D &&
-         intelImage->base.Depth == 1)))
-      return;
-
-   /* If this image disrespects BaseLevel, allocate from level zero.
-    * Usually BaseLevel == 0, so it's unlikely to happen.
-    */
-   if (intelImage->level < intelObj->base.BaseLevel)
-      firstLevel = 0;
-   else
-      firstLevel = intelObj->base.BaseLevel;
-
+      return NULL;
 
    /* Figure out image dimensions at start level. 
     */
-   for (i = intelImage->level; i > firstLevel; i--) {
+   for (i = intelImage->level; i > 0; i--) {
       width <<= 1;
       if (height != 1)
          height <<= 1;
@@ -108,34 +79,29 @@ guess_and_alloc_mipmap_tree(struct intel_context *intel,
     */
    if ((intelObj->base.MinFilter == GL_NEAREST ||
         intelObj->base.MinFilter == GL_LINEAR) &&
-       intelImage->level == firstLevel &&
-       (intel->gen < 4 || firstLevel == 0)) {
-      lastLevel = firstLevel;
+       intelImage->level == 0) {
+      lastLevel = 0;
    }
    else {
-      lastLevel = firstLevel + logbase2(MAX2(MAX2(width, height), depth));
+      lastLevel = logbase2(MAX2(MAX2(width, height), depth));
    }
 
-   assert(!intelObj->mt);
    if (_mesa_is_format_compressed(intelImage->base.TexFormat))
       comp_byte = intel_compressed_num_bytes(intelImage->base.TexFormat);
 
    texelBytes = _mesa_get_format_bytes(intelImage->base.TexFormat);
 
-   intelObj->mt = intel_miptree_create(intel,
-                                       intelObj->base.Target,
-                                       intelImage->base._BaseFormat,
-                                       intelImage->base.InternalFormat,
-                                       firstLevel,
-                                       lastLevel,
-                                       width,
-                                       height,
-                                       depth,
-                                       texelBytes,
-                                       comp_byte,
-				       expect_accelerated_upload);
-
-   DBG("%s - success\n", __FUNCTION__);
+   return intel_miptree_create(intel,
+			       intelObj->base.Target,
+			       intelImage->base._BaseFormat,
+			       intelImage->base.InternalFormat,
+			       lastLevel + 1,
+			       width,
+			       height,
+			       depth,
+			       texelBytes,
+			       comp_byte,
+			       expect_accelerated_upload);
 }
 
 
@@ -343,41 +309,23 @@ intelTexImage(struct gl_context * ctx,
       texImage->Data = NULL;
    }
 
-   if (!intelObj->mt) {
-      guess_and_alloc_mipmap_tree(intel, intelObj, intelImage, pixels == NULL);
-      if (!intelObj->mt) {
-	 DBG("guess_and_alloc_mipmap_tree: failed\n");
-      }
-   }
-
-   assert(!intelImage->mt);
-
-   if (intelObj->mt &&
-       intel_miptree_match_image(intelObj->mt, &intelImage->base)) {
-
+   if (intelObj->mt && intel_miptree_match_image(intelObj->mt,
+						 &intelImage->base)) {
       intel_miptree_reference(&intelImage->mt, intelObj->mt);
-      assert(intelImage->mt);
-   } else if (intelImage->base.Border == 0) {
-      int comp_byte = 0;
-      GLuint texelBytes = _mesa_get_format_bytes(intelImage->base.TexFormat);
-      GLenum baseFormat = _mesa_get_format_base_format(intelImage->base.TexFormat);
-      if (_mesa_is_format_compressed(intelImage->base.TexFormat)) {
-	 comp_byte =
-	    intel_compressed_num_bytes(intelImage->base.TexFormat);
+   } else {
+      intel_miptree_release(intel, &intelImage->mt);
+      intelImage->mt = intel_miptree_create_for_teximage(intel, intelObj,
+							 intelImage,
+							 pixels == NULL);
+      if (!intelImage->mt) {
+	 DBG("guess_and_alloc_mipmap_tree: failed\n");
       }
 
-      /* Didn't fit in the object miptree, but it's suitable for inclusion in
-       * a miptree, so create one just for our level and store it in the image.
-       * It'll get moved into the object miptree at validate time.
+      /* Speculatively set up the object with this miptree so that the
+       * later levels can just load into the miptree we just made.
        */
-      intelImage->mt = intel_miptree_create(intel, target,
-					    baseFormat,
-					    internalFormat,
-					    level, level,
-					    width, height, depth,
-					    texelBytes,
-					    comp_byte, pixels == NULL);
-
+      if (!intelObj->mt && intelImage->mt)
+	 intel_miptree_reference(&intelObj->mt, intelImage->mt);
    }
 
    /* PBO fastpaths:
@@ -396,10 +344,7 @@ intelTexImage(struct gl_context * ctx,
        * performance (in particular when intel_region_cow() is
        * required).
        */
-      if (intelObj->mt == intelImage->mt &&
-          intelObj->mt->first_level == level &&
-          intelObj->mt->last_level == level) {
-
+      if (intelImage->mt->levels == 1) {
          if (try_pbo_zcopy(intel, intelImage, unpack,
                            internalFormat,
                            width, height, format, type, pixels)) {