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Commit 2549d6c2 authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915: Avoid vmallocing a buffer for the relocations 



... perform an access validation check up front instead and copy them in
on-demand, during i915_gem_object_pin_and_relocate(). As around 20% of
the CPU overhead may be spent inside vmalloc for the relocation entries
when submitting an execbuffer [for x11perf -aa10text], the savings are
considerable and result in around a 10% throughput increase [for glyphs].

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
parent 55b7d6e8

drivers/gpu/drm/i915/i915_gem.c

+75 −149
Original line number Diff line number Diff line
@@ -3291,12 +3291,12 @@ i915_gem_object_set_cpu_read_domain_range(struct drm_gem_object *obj, 
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,

				 struct drm_i915_gem_relocation_entry *relocs)

				 struct drm_i915_gem_exec_object2 *entry)

{

	struct drm_device *dev = obj->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;

	void __iomem *reloc_page;

	bool need_fence;
@@ -3337,15 +3337,24 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj, 
	/* 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= &relocs[i];

		struct drm_i915_gem_relocation_entry reloc;

		struct drm_gem_object *target_obj;

		struct drm_i915_gem_object *target_obj_priv;

		uint32_t reloc_val, reloc_offset;

		uint32_t __iomem *reloc_entry;



		ret = __copy_from_user_inatomic(&reloc,

						user_relocs+i,

						sizeof(reloc));

		if (ret) {

			i915_gem_object_unpin(obj);

			return -EFAULT;

		}



		target_obj = drm_gem_object_lookup(obj->dev, file_priv,

						   reloc->target_handle);

						   reloc.target_handle);

		if (target_obj == NULL) {

			i915_gem_object_unpin(obj);

			return -ENOENT;
@@ -3358,13 +3367,13 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj, 
			 "presumed %08x delta %08x\n",

			 __func__,

			 obj,

			 (int) reloc->offset,

			 (int) reloc->target_handle,

			 (int) reloc->read_domains,

			 (int) reloc->write_domain,

			 (int) reloc.offset,

			 (int) reloc.target_handle,

			 (int) reloc.read_domains,

			 (int) reloc.write_domain,

			 (int) target_obj_priv->gtt_offset,

			 (int) reloc->presumed_offset,

			 reloc->delta);

			 (int) reloc.presumed_offset,

			 reloc.delta);

#endif



		/* The target buffer should have appeared before us in the
@@ -3372,89 +3381,89 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj, 
		 */

		if (target_obj_priv->gtt_space == NULL) {

			DRM_ERROR("No GTT space found for object %d\n",

				  reloc->target_handle);

				  reloc.target_handle);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}



		/* Validate that the target is in a valid r/w GPU domain */

		if (reloc->write_domain & (reloc->write_domain - 1)) {

		if (reloc.write_domain & (reloc.write_domain - 1)) {

			DRM_ERROR("reloc with multiple write domains: "

				  "obj %p target %d offset %d "

				  "read %08x write %08x",

				  obj, reloc->target_handle,

				  (int) reloc->offset,

				  reloc->read_domains,

				  reloc->write_domain);

				  obj, reloc.target_handle,

				  (int) reloc.offset,

				  reloc.read_domains,

				  reloc.write_domain);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}

		if (reloc->write_domain & I915_GEM_DOMAIN_CPU ||

		    reloc->read_domains & I915_GEM_DOMAIN_CPU) {

		if (reloc.write_domain & I915_GEM_DOMAIN_CPU ||

		    reloc.read_domains & I915_GEM_DOMAIN_CPU) {

			DRM_ERROR("reloc with read/write CPU domains: "

				  "obj %p target %d offset %d "

				  "read %08x write %08x",

				  obj, reloc->target_handle,

				  (int) reloc->offset,

				  reloc->read_domains,

				  reloc->write_domain);

				  obj, reloc.target_handle,

				  (int) reloc.offset,

				  reloc.read_domains,

				  reloc.write_domain);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}

		if (reloc->write_domain && target_obj->pending_write_domain &&

		    reloc->write_domain != target_obj->pending_write_domain) {

		if (reloc.write_domain && target_obj->pending_write_domain &&

		    reloc.write_domain != target_obj->pending_write_domain) {

			DRM_ERROR("Write domain conflict: "

				  "obj %p target %d offset %d "

				  "new %08x old %08x\n",

				  obj, reloc->target_handle,

				  (int) reloc->offset,

				  reloc->write_domain,

				  obj, reloc.target_handle,

				  (int) reloc.offset,

				  reloc.write_domain,

				  target_obj->pending_write_domain);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}



		target_obj->pending_read_domains |= reloc->read_domains;

		target_obj->pending_write_domain |= reloc->write_domain;

		target_obj->pending_read_domains |= reloc.read_domains;

		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) {

		if (target_obj_priv->gtt_offset == reloc.presumed_offset) {

			drm_gem_object_unreference(target_obj);

			continue;

		}



		/* Check that the relocation address is valid... */

		if (reloc->offset > obj->size - 4) {

		if (reloc.offset > obj->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);

				  obj, reloc.target_handle,

				  (int) reloc.offset, (int) obj->size);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}

		if (reloc->offset & 3) {

		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);

				  obj, reloc.target_handle,

				  (int) reloc.offset);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;

		}



		/* and points to somewhere within the target object. */

		if (reloc->delta >= target_obj->size) {

		if (reloc.delta >= target_obj->size) {

			DRM_ERROR("Relocation beyond target object bounds: "

				  "obj %p target %d delta %d size %d.\n",

				  obj, reloc->target_handle,

				  (int) reloc->delta, (int) target_obj->size);

				  obj, reloc.target_handle,

				  (int) reloc.delta, (int) target_obj->size);

			drm_gem_object_unreference(target_obj);

			i915_gem_object_unpin(obj);

			return -EINVAL;
@@ -3470,23 +3479,18 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj, 
		/* Map the page containing the relocation we're going to

		 * perform.

		 */

		reloc_offset = obj_priv->gtt_offset + reloc->offset;

		reloc_offset = obj_priv->gtt_offset + reloc.offset;

		reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,

						      (reloc_offset &

						       ~(PAGE_SIZE - 1)),

						      KM_USER0);

		reloc_entry = (uint32_t __iomem *)(reloc_page +

						   (reloc_offset & (PAGE_SIZE - 1)));

		reloc_val = target_obj_priv->gtt_offset + reloc->delta;

		reloc_val = target_obj_priv->gtt_offset + reloc.delta;



		writel(reloc_val, reloc_entry);

		io_mapping_unmap_atomic(reloc_page, KM_USER0);



		/* The updated presumed offset for this entry will be

		 * copied back out to the user.

		 */

		reloc->presumed_offset = target_obj_priv->gtt_offset;



		drm_gem_object_unreference(target_obj);

	}
@@ -3551,98 +3555,40 @@ i915_gem_ring_throttle(struct drm_device *dev, struct drm_file *file) 
}



static int

i915_gem_get_relocs_from_user(struct drm_i915_gem_exec_object2 *exec_list,

			      uint32_t buffer_count,

			      struct drm_i915_gem_relocation_entry **relocs)

i915_gem_check_execbuffer(struct drm_i915_gem_execbuffer2 *exec,

			  uint64_t exec_offset)

{

	uint32_t reloc_count = 0, reloc_index = 0, i;

	int ret;



	*relocs = NULL;

	for (i = 0; i < buffer_count; i++) {

		if (reloc_count + exec_list[i].relocation_count < reloc_count)

			return -EINVAL;

		reloc_count += exec_list[i].relocation_count;

	}



	*relocs = drm_calloc_large(reloc_count, sizeof(**relocs));

	if (*relocs == NULL) {

		DRM_ERROR("failed to alloc relocs, count %d\n", reloc_count);

		return -ENOMEM;

	}



	for (i = 0; i < buffer_count; i++) {

		struct drm_i915_gem_relocation_entry __user *user_relocs;

	uint32_t exec_start, exec_len;



		user_relocs = (void __user *)(uintptr_t)exec_list[i].relocs_ptr;

	exec_start = (uint32_t) exec_offset + exec->batch_start_offset;

	exec_len = (uint32_t) exec->batch_len;



		ret = copy_from_user(&(*relocs)[reloc_index],

				     user_relocs,

				     exec_list[i].relocation_count *

				     sizeof(**relocs));

		if (ret != 0) {

			drm_free_large(*relocs);

			*relocs = NULL;

			return -EFAULT;

		}

	if ((exec_start | exec_len) & 0x7)

		return -EINVAL;



		reloc_index += exec_list[i].relocation_count;

	}

	if (!exec_start)

		return -EINVAL;



	return 0;

}



static int

i915_gem_put_relocs_to_user(struct drm_i915_gem_exec_object2 *exec_list,

			    uint32_t buffer_count,

			    struct drm_i915_gem_relocation_entry *relocs)

validate_exec_list(struct drm_i915_gem_exec_object2 *exec,

		   int count)

{

	uint32_t reloc_count = 0, i;

	int ret = 0;



	if (relocs == NULL)

	    return 0;



	for (i = 0; i < buffer_count; i++) {

		struct drm_i915_gem_relocation_entry __user *user_relocs;

		int unwritten;



		user_relocs = (void __user *)(uintptr_t)exec_list[i].relocs_ptr;



		unwritten = copy_to_user(user_relocs,

					 &relocs[reloc_count],

					 exec_list[i].relocation_count *

					 sizeof(*relocs));



		if (unwritten) {

			ret = -EFAULT;

			goto err;

		}

	int i;



		reloc_count += exec_list[i].relocation_count;

	}

	for (i = 0; i < count; i++) {

		char __user *ptr = (char __user *)(uintptr_t)exec[i].relocs_ptr;

		size_t length = exec[i].relocation_count * sizeof(struct drm_i915_gem_relocation_entry);



err:

	drm_free_large(relocs);

		if (!access_ok(VERIFY_READ, ptr, length))

			return -EFAULT;



	return ret;

		if (fault_in_pages_readable(ptr, length))

			return -EFAULT;

	}



static int

i915_gem_check_execbuffer (struct drm_i915_gem_execbuffer2 *exec,

			   uint64_t exec_offset)

{

	uint32_t exec_start, exec_len;



	exec_start = (uint32_t) exec_offset + exec->batch_start_offset;

	exec_len = (uint32_t) exec->batch_len;



	if ((exec_start | exec_len) & 0x7)

		return -EINVAL;



	if (!exec_start)

		return -EINVAL;



	return 0;

}
@@ -3657,11 +3603,9 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data, 
	struct drm_gem_object *batch_obj;

	struct drm_i915_gem_object *obj_priv;

	struct drm_clip_rect *cliprects = NULL;

	struct drm_i915_gem_relocation_entry *relocs = NULL;

	struct drm_i915_gem_request *request = NULL;

	int ret, ret2, i, pinned = 0;

	int ret, i, pinned = 0;

	uint64_t exec_offset;

	uint32_t reloc_index;

	int pin_tries, flips;



	struct intel_ring_buffer *ring = NULL;
@@ -3670,6 +3614,10 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data, 
	if (ret)

		return ret;



	ret = validate_exec_list(exec_list, args->buffer_count);

	if (ret)

		return ret;



#if WATCH_EXEC

	DRM_INFO("buffers_ptr %d buffer_count %d len %08x\n",

		  (int) args->buffers_ptr, args->buffer_count, args->batch_len);
@@ -3722,11 +3670,6 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data, 
		goto pre_mutex_err;

	}



	ret = i915_gem_get_relocs_from_user(exec_list, args->buffer_count,

					    &relocs);

	if (ret != 0)

		goto pre_mutex_err;



	ret = i915_mutex_lock_interruptible(dev);

	if (ret)

		goto pre_mutex_err;
@@ -3765,19 +3708,16 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data, 
	/* Pin and relocate */

	for (pin_tries = 0; ; pin_tries++) {

		ret = 0;

		reloc_index = 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],

							       &relocs[reloc_index]);

							       &exec_list[i]);

			if (ret)

				break;

			pinned = i + 1;

			reloc_index += exec_list[i].relocation_count;

		}

		/* success */

		if (ret == 0)
@@ -3967,20 +3907,6 @@ err: 
	mutex_unlock(&dev->struct_mutex);



pre_mutex_err:

	/* Copy the updated relocations out regardless of current error

	 * state.  Failure to update the relocs would mean that the next

	 * time userland calls execbuf, it would do so with presumed offset

	 * state that didn't match the actual object state.

	 */

	ret2 = i915_gem_put_relocs_to_user(exec_list, args->buffer_count,

					   relocs);

	if (ret2 != 0) {

		DRM_ERROR("Failed to copy relocations back out: %d\n", ret2);



		if (ret == 0)

			ret = ret2;

	}



	drm_free_large(object_list);

	kfree(cliprects);

	kfree(request);