drm/i915: cache the last object lookup during pin_and_relocate()

The most frequent relocation within a batchbuffer is a contiguous sequence
of vertex buffer relocations, for which we can virtually eliminate the
drm_gem_object_lookup() overhead by caching the last handle to object
translation.

In doing so we refactor the pin and relocate retry loop out of
do_execbuffer into its own helper function and so improve the error
paths.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 144 insertions, 171 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 34a07fc20513..f6a615ea3025 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2152,6 +2152,7 @@ i915_gem_object_unbind(struct drm_gem_object *obj)
 
         drm_mm_put_block(obj_priv->gtt_space);
         obj_priv->gtt_space = NULL;
+        obj_priv->gtt_offset = 0;
 
         if (i915_gem_object_is_purgeable(obj_priv))
                 i915_gem_object_truncate(obj);
@@ -2645,12 +2646,9 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
  search_free:
         free_space = drm_mm_search_free(&dev_priv->mm.gtt_space,
                                         obj->size, alignment, 0);
-        if (free_space != NULL) {
+        if (free_space != NULL)
                 obj_priv->gtt_space = drm_mm_get_block(free_space, obj->size,
                                                        alignment);
-                if (obj_priv->gtt_space != NULL)
-                        obj_priv->gtt_offset = obj_priv->gtt_space->start;
-        }
         if (obj_priv->gtt_space == NULL) {
                 /* If the gtt is empty and we're still having trouble
                  * fitting our object in, we're out of memory.
@@ -2693,7 +2691,7 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
         obj_priv->agp_mem = drm_agp_bind_pages(dev,
                                                obj_priv->pages,
                                                obj->size >> PAGE_SHIFT,
-                                               obj_priv->gtt_offset,
+                                               obj_priv->gtt_space->start,
                                                obj_priv->agp_type);
         if (obj_priv->agp_mem == NULL) {
                 i915_gem_object_put_pages(obj);
@@ -2718,6 +2716,7 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
         BUG_ON(obj->read_domains & I915_GEM_GPU_DOMAINS);
         BUG_ON(obj->write_domain & I915_GEM_GPU_DOMAINS);
 
+        obj_priv->gtt_offset = obj_priv->gtt_space->start;
         trace_i915_gem_object_bind(obj, obj_priv->gtt_offset);
 
         return 0;
@@ -3240,74 +3239,42 @@ i915_gem_object_set_cpu_read_domain_range(struct drm_gem_object *obj,
  * Pin an object to the GTT and evaluate the relocations landing in it.
  */
 static int
-i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
-                                 struct drm_file *file_priv,
-                                 struct drm_i915_gem_exec_object2 *entry)
+i915_gem_execbuffer_relocate(struct drm_i915_gem_object *obj,
+                             struct drm_file *file_priv,
+                             struct drm_i915_gem_exec_object2 *entry)
 {
-        struct drm_device *dev = obj->dev;
+        struct drm_device *dev = obj->base.dev;
         drm_i915_private_t *dev_priv = dev->dev_private;
-        struct drm_i915_gem_object *obj_priv = to_intel_bo(obj);
         struct drm_i915_gem_relocation_entry __user *user_relocs;
-        int i, ret;
-        bool need_fence;
-
-        need_fence = entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
-                     obj_priv->tiling_mode != I915_TILING_NONE;
-
-        /* Check fence reg constraints and rebind if necessary */
-        if (need_fence &&
-            !i915_gem_object_fence_offset_ok(obj,
-                                             obj_priv->tiling_mode)) {
-                ret = i915_gem_object_unbind(obj);
-                if (ret)
-                        return ret;
-        }
-
-        /* Choose the GTT offset for our buffer and put it there. */
-        ret = i915_gem_object_pin(obj, (uint32_t) entry->alignment);
-        if (ret)
-                return ret;
-
-        /*
-         * Pre-965 chips need a fence register set up in order to
-         * properly handle blits to/from tiled surfaces.
-         */
-        if (need_fence) {
-                ret = i915_gem_object_get_fence_reg(obj, true);
-                if (ret != 0) {
-                        i915_gem_object_unpin(obj);
-                        return ret;
-                }
+        struct drm_gem_object *target_obj = NULL;
+        uint32_t target_handle = 0;
+        int i, ret = 0;
 
-                dev_priv->fence_regs[obj_priv->fence_reg].gpu = true;
-        }
-
-        entry->offset = obj_priv->gtt_offset;
-
-        /* Apply the relocations, using the GTT aperture to avoid cache
-         * flushing requirements.
-         */
         user_relocs = (void __user *)(uintptr_t)entry->relocs_ptr;
         for (i = 0; i < entry->relocation_count; i++) {
                 struct drm_i915_gem_relocation_entry reloc;
-                struct drm_gem_object *target_obj;
-                struct drm_i915_gem_object *target_obj_priv;
+                uint32_t target_offset;
 
-                ret = __copy_from_user_inatomic(&reloc,
-                                                user_relocs+i,
-                                                sizeof(reloc));
-                if (ret) {
-                        i915_gem_object_unpin(obj);
-                        return -EFAULT;
+                if (__copy_from_user_inatomic(&reloc,
+                                              user_relocs+i,
+                                              sizeof(reloc))) {
+                        ret = -EFAULT;
+                        break;
                 }
 
-                target_obj = drm_gem_object_lookup(obj->dev, file_priv,
-                                                   reloc.target_handle);
-                if (target_obj == NULL) {
-                        i915_gem_object_unpin(obj);
-                        return -ENOENT;
+                if (reloc.target_handle != target_handle) {
+                        drm_gem_object_unreference(target_obj);
+
+                        target_obj = drm_gem_object_lookup(dev, file_priv,
+                                                           reloc.target_handle);
+                        if (target_obj == NULL) {
+                                ret = -ENOENT;
+                                break;
+                        }
+
+                        target_handle = reloc.target_handle;
                 }
-                target_obj_priv = to_intel_bo(target_obj);
+                target_offset = to_intel_bo(target_obj)->gtt_offset;
 
 #if WATCH_RELOC
                 DRM_INFO("%s: obj %p offset %08x target %d "
@@ -3319,7 +3286,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                          (int) reloc.target_handle,
                          (int) reloc.read_domains,
                          (int) reloc.write_domain,
-                         (int) target_obj_priv->gtt_offset,
+                         (int) target_offset,
                          (int) reloc.presumed_offset,
                          reloc.delta);
 #endif
@@ -3327,12 +3294,11 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                 /* The target buffer should have appeared before us in the
                  * exec_object list, so it should have a GTT space bound by now.
                  */
-                if (target_obj_priv->gtt_space == NULL) {
+                if (target_offset == 0) {
                         DRM_ERROR("No GTT space found for object %d\n",
                                   reloc.target_handle);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
 
                 /* Validate that the target is in a valid r/w GPU domain */
@@ -3344,9 +3310,8 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                                   (int) reloc.offset,
                                   reloc.read_domains,
                                   reloc.write_domain);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
                 if (reloc.write_domain & I915_GEM_DOMAIN_CPU ||
                     reloc.read_domains & I915_GEM_DOMAIN_CPU) {
@@ -3357,9 +3322,8 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                                   (int) reloc.offset,
                                   reloc.read_domains,
                                   reloc.write_domain);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
                 if (reloc.write_domain && target_obj->pending_write_domain &&
                     reloc.write_domain != target_obj->pending_write_domain) {
@@ -3370,40 +3334,35 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                                   (int) reloc.offset,
                                   reloc.write_domain,
                                   target_obj->pending_write_domain);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
 
                 target_obj->pending_read_domains |= reloc.read_domains;
-                target_obj->pending_write_domain |= reloc.write_domain;
+                target_obj->pending_write_domain = reloc.write_domain;
 
                 /* If the relocation already has the right value in it, no
                  * more work needs to be done.
                  */
-                if (target_obj_priv->gtt_offset == reloc.presumed_offset) {
-                        drm_gem_object_unreference(target_obj);
+                if (target_offset == reloc.presumed_offset)
                         continue;
-                }
 
                 /* Check that the relocation address is valid... */
-                if (reloc.offset > obj->size - 4) {
+                if (reloc.offset > obj->base.size - 4) {
                         DRM_ERROR("Relocation beyond object bounds: "
                                   "obj %p target %d offset %d size %d.\n",
                                   obj, reloc.target_handle,
-                                  (int) reloc.offset, (int) obj->size);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                                  (int) reloc.offset, (int) obj->base.size);
+                        ret = -EINVAL;
+                        break;
                 }
                 if (reloc.offset & 3) {
                         DRM_ERROR("Relocation not 4-byte aligned: "
                                   "obj %p target %d offset %d.\n",
                                   obj, reloc.target_handle,
                                   (int) reloc.offset);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
 
                 /* and points to somewhere within the target object. */
@@ -3412,33 +3371,28 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                                   "obj %p target %d delta %d size %d.\n",
                                   obj, reloc.target_handle,
                                   (int) reloc.delta, (int) target_obj->size);
-                        drm_gem_object_unreference(target_obj);
-                        i915_gem_object_unpin(obj);
-                        return -EINVAL;
+                        ret = -EINVAL;
+                        break;
                 }
 
-                reloc.delta += target_obj_priv->gtt_offset;
-                if (obj->write_domain == I915_GEM_DOMAIN_CPU) {
+                reloc.delta += target_offset;
+                if (obj->base.write_domain == I915_GEM_DOMAIN_CPU) {
                         uint32_t page_offset = reloc.offset & ~PAGE_MASK;
                         char *vaddr;
 
-                        vaddr = kmap_atomic(obj_priv->pages[reloc.offset >> PAGE_SHIFT], KM_USER0);
+                        vaddr = kmap_atomic(obj->pages[reloc.offset >> PAGE_SHIFT], KM_USER0);
                         *(uint32_t *)(vaddr + page_offset) = reloc.delta;
                         kunmap_atomic(vaddr, KM_USER0);
                 } else {
                         uint32_t __iomem *reloc_entry;
                         void __iomem *reloc_page;
-                        int ret;
 
-                        ret = i915_gem_object_set_to_gtt_domain(obj, 1);
-                        if (ret) {
-                                drm_gem_object_unreference(target_obj);
-                                i915_gem_object_unpin(obj);
-                                return ret;
-                        }
+                        ret = i915_gem_object_set_to_gtt_domain(&obj->base, 1);
+                        if (ret)
+                                break;
 
                         /* Map the page containing the relocation we're going to perform.  */
-                        reloc.offset += obj_priv->gtt_offset;
+                        reloc.offset += obj->gtt_offset;
                         reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
                                                               reloc.offset & PAGE_MASK,
                                                               KM_USER0);
@@ -3447,8 +3401,74 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                         iowrite32(reloc.delta, reloc_entry);
                         io_mapping_unmap_atomic(reloc_page, KM_USER0);
                 }
+        }
+
+        drm_gem_object_unreference(target_obj);
+        return ret;
+}
+
+static int
+i915_gem_execbuffer_pin(struct drm_device *dev,
+                        struct drm_file *file,
+                        struct drm_gem_object **object_list,
+                        struct drm_i915_gem_exec_object2 *exec_list,
+                        int count)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        int ret, i, retry;
+
+        /* attempt to pin all of the buffers into the GTT */
+        for (retry = 0; retry < 2; retry++) {
+                ret = 0;
+                for (i = 0; i < count; i++) {
+                        struct drm_i915_gem_exec_object2 *entry = &exec_list[i];
+                        struct drm_i915_gem_object *obj= to_intel_bo(object_list[i]);
+                        bool need_fence =
+                                entry->flags & EXEC_OBJECT_NEEDS_FENCE &&
+                                obj->tiling_mode != I915_TILING_NONE;
+
+                        /* Check fence reg constraints and rebind if necessary */
+                        if (need_fence &&
+                            !i915_gem_object_fence_offset_ok(&obj->base,
+                                                             obj->tiling_mode)) {
+                                ret = i915_gem_object_unbind(&obj->base);
+                                if (ret)
+                                        break;
+                        }
+
+                        ret = i915_gem_object_pin(&obj->base, entry->alignment);
+                        if (ret)
+                                break;
+
+                        /*
+                         * Pre-965 chips need a fence register set up in order
+                         * to properly handle blits to/from tiled surfaces.
+                         */
+                        if (need_fence) {
+                                ret = i915_gem_object_get_fence_reg(&obj->base, true);
+                                if (ret) {
+                                        i915_gem_object_unpin(&obj->base);
+                                        break;
+                                }
+
+                                dev_priv->fence_regs[obj->fence_reg].gpu = true;
+                        }
+
+                        entry->offset = obj->gtt_offset;
+                }
 
-                drm_gem_object_unreference(target_obj);
+                while (i--)
+                        i915_gem_object_unpin(object_list[i]);
+
+                if (ret == 0)
+                        break;
+
+                if (ret != -ENOSPC || retry)
+                        return ret;
+
+                ret = i915_gem_evict_everything(dev);
+                if (ret)
+                        return ret;
         }
 
         return 0;
@@ -3551,7 +3571,7 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec,
 
 static int
 i915_gem_do_execbuffer(struct drm_device *dev, void *data,
-                       struct drm_file *file_priv,
+                       struct drm_file *file,
                        struct drm_i915_gem_execbuffer2 *args,
                        struct drm_i915_gem_exec_object2 *exec_list)
 {
@@ -3561,9 +3581,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
         struct drm_i915_gem_object *obj_priv;
         struct drm_clip_rect *cliprects = NULL;
         struct drm_i915_gem_request *request = NULL;
-        int ret, i, pinned = 0;
+        int ret, i, flips;
         uint64_t exec_offset;
-        int pin_tries, flips;
 
         struct intel_ring_buffer *ring = NULL;
 
@@ -3639,7 +3658,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
 
         /* Look up object handles */
         for (i = 0; i < args->buffer_count; i++) {
-                object_list[i] = drm_gem_object_lookup(dev, file_priv,
+                object_list[i] = drm_gem_object_lookup(dev, file,
                                                        exec_list[i].handle);
                 if (object_list[i] == NULL) {
                         DRM_ERROR("Invalid object handle %d at index %d\n",
@@ -3662,63 +3681,20 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                 obj_priv->in_execbuffer = true;
         }
 
-        /* Pin and relocate */
-        for (pin_tries = 0; ; pin_tries++) {
-                ret = 0;
-
-                for (i = 0; i < args->buffer_count; i++) {
-                        object_list[i]->pending_read_domains = 0;
-                        object_list[i]->pending_write_domain = 0;
-                        ret = i915_gem_object_pin_and_relocate(object_list[i],
-                                                               file_priv,
-                                                               &exec_list[i]);
-                        if (ret)
-                                break;
-                        pinned = i + 1;
-                }
-                /* success */
-                if (ret == 0)
-                        break;
-
-                /* error other than GTT full, or we've already tried again */
-                if (ret != -ENOSPC || pin_tries >= 1) {
-                        if (ret != -ERESTARTSYS) {
-                                unsigned long long total_size = 0;
-                                int num_fences = 0;
-                                for (i = 0; i < args->buffer_count; i++) {
-                                        obj_priv = to_intel_bo(object_list[i]);
-
-                                        total_size += object_list[i]->size;
-                                        num_fences +=
-                                                exec_list[i].flags & EXEC_OBJECT_NEEDS_FENCE &&
-                                                obj_priv->tiling_mode != I915_TILING_NONE;
-                                }
-                                DRM_ERROR("Failed to pin buffer %d of %d, total %llu bytes, %d fences: %d\n",
-                                          pinned+1, args->buffer_count,
-                                          total_size, num_fences,
-                                          ret);
-                                DRM_ERROR("%u objects [%u pinned, %u GTT], "
-                                          "%zu object bytes [%zu pinned], "
-                                          "%zu /%zu gtt bytes\n",
-                                          dev_priv->mm.object_count,
-                                          dev_priv->mm.pin_count,
-                                          dev_priv->mm.gtt_count,
-                                          dev_priv->mm.object_memory,
-                                          dev_priv->mm.pin_memory,
-                                          dev_priv->mm.gtt_memory,
-                                          dev_priv->mm.gtt_total);
-                        }
-                        goto err;
-                }
-
-                /* unpin all of our buffers */
-                for (i = 0; i < pinned; i++)
-                        i915_gem_object_unpin(object_list[i]);
-                pinned = 0;
+        /* Move the objects en-masse into the GTT, evicting if necessary. */
+        ret = i915_gem_execbuffer_pin(dev, file,
+                                      object_list, exec_list,
+                                      args->buffer_count);
+        if (ret)
+                goto err;
 
-                /* evict everyone we can from the aperture */
-                ret = i915_gem_evict_everything(dev);
-                if (ret && ret != -ENOSPC)
+        /* The objects are in their final locations, apply the relocations. */
+        for (i = 0; i < args->buffer_count; i++) {
+                struct drm_i915_gem_object *obj = to_intel_bo(object_list[i]);
+                obj->base.pending_read_domains = 0;
+                obj->base.pending_write_domain = 0;
+                ret = i915_gem_execbuffer_relocate(obj, file, &exec_list[i]);
+                if (ret)
                         goto err;
         }
 
@@ -3731,9 +3707,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
         }
         batch_obj->pending_read_domains |= I915_GEM_DOMAIN_COMMAND;
 
-        /* Sanity check the batch buffer, prior to moving objects */
-        exec_offset = exec_list[args->buffer_count - 1].offset;
-        ret = i915_gem_check_execbuffer (args, exec_offset);
+        /* Sanity check the batch buffer */
+        exec_offset = to_intel_bo(batch_obj)->gtt_offset;
+        ret = i915_gem_check_execbuffer(args, exec_offset);
         if (ret != 0) {
                 DRM_ERROR("execbuf with invalid offset/length\n");
                 goto err;
@@ -3761,7 +3737,7 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                          dev->invalidate_domains,
                          dev->flush_domains);
 #endif
-                i915_gem_flush(dev, file_priv,
+                i915_gem_flush(dev, file,
                                dev->invalidate_domains,
                                dev->flush_domains,
                                dev_priv->mm.flush_rings);
@@ -3846,13 +3822,10 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
                 i915_gem_object_move_to_active(obj, ring);
         }
 
-        i915_add_request(dev, file_priv, request, ring);
+        i915_add_request(dev, file, request, ring);
         request = NULL;
 
 err:
-        for (i = 0; i < pinned; i++)
-                i915_gem_object_unpin(object_list[i]);
-
         for (i = 0; i < args->buffer_count; i++) {
                 if (object_list[i]) {
                         obj_priv = to_intel_bo(object_list[i]);