ankitprasad.r.sharma@xxxxxxxxx writes:
> From: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
>
> In pwrite_fast, map an object page by page if obj_ggtt_pin fails. First,
> we try a nonblocking pin for the whole object (since that is fastest if
> reused), then failing that we try to grab one page in the mappable
> aperture. It also allows us to handle objects larger than the mappable
> aperture (e.g. if we need to pwrite with vGPU restricting the aperture
> to a measely 8MiB or something like that).
>
> v2: Pin pages before starting pwrite, Combined duplicate loops (Chris)
>
> v3: Combined loops based on local patch by Chris (Chris)
>
> Signed-off-by: Ankitprasad Sharma <ankitprasad.r.sharma@xxxxxxxxx>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_gem.c | 75 +++++++++++++++++++++++++++++------------
> 1 file changed, 53 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
> index f1e3fde..9d2e6e3 100644
> --- a/drivers/gpu/drm/i915/i915_gem.c
> +++ b/drivers/gpu/drm/i915/i915_gem.c
> @@ -760,20 +760,33 @@ fast_user_write(struct io_mapping *mapping,
> * user into the GTT, uncached.
> */
> static int
> -i915_gem_gtt_pwrite_fast(struct drm_device *dev,
> +i915_gem_gtt_pwrite_fast(struct drm_i915_private *i915,
> struct drm_i915_gem_object *obj,
> struct drm_i915_gem_pwrite *args,
> struct drm_file *file)
> {
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - ssize_t remain;
> - loff_t offset, page_base;
> + struct drm_mm_node node;
> + uint64_t remain, offset;
> char __user *user_data;
> - int page_offset, page_length, ret;
> + int ret;
>
> ret = i915_gem_obj_ggtt_pin(obj, 0, PIN_MAPPABLE | PIN_NONBLOCK);
> - if (ret)
> - goto out;
> + if (ret) {
> + memset(&node, 0, sizeof(node));
> + ret = drm_mm_insert_node_in_range_generic(&i915->gtt.base.mm,
> + &node, 4096, 0,
> + I915_CACHE_NONE, 0,
> + i915->gtt.mappable_end,
> + DRM_MM_SEARCH_DEFAULT,
> + DRM_MM_CREATE_DEFAULT);
> + if (ret)
> + goto out;
> +
> + i915_gem_object_pin_pages(obj);
> + } else {
> + node.start = i915_gem_obj_ggtt_offset(obj);
> + node.allocated = false;
> + }
>
> ret = i915_gem_object_set_to_gtt_domain(obj, true);
> if (ret)
> @@ -783,31 +796,39 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev,
> if (ret)
> goto out_unpin;
>
> - user_data = to_user_ptr(args->data_ptr);
> - remain = args->size;
> -
> - offset = i915_gem_obj_ggtt_offset(obj) + args->offset;
> -
> intel_fb_obj_invalidate(obj, ORIGIN_GTT);
> + obj->dirty = true;
>
> - while (remain > 0) {
> + user_data = to_user_ptr(args->data_ptr);
> + offset = args->offset;
> + remain = args->size;
> + while (remain) {
> /* Operation in this page
> *
> * page_base = page offset within aperture
> * page_offset = offset within page
> * page_length = bytes to copy for this page
> */
> - page_base = offset & PAGE_MASK;
> - page_offset = offset_in_page(offset);
> - page_length = remain;
> - if ((page_offset + remain) > PAGE_SIZE)
> - page_length = PAGE_SIZE - page_offset;
> -
> + u32 page_base = node.start;
You truncate here as node.start is 64bit offset into the vm area.
-Mika
> + unsigned page_offset = offset_in_page(offset);
> + unsigned page_length = PAGE_SIZE - page_offset;
> + page_length = remain < page_length ? remain : page_length;
> + if (node.allocated) {
> + wmb();
> + i915->gtt.base.insert_page(&i915->gtt.base,
> + i915_gem_object_get_dma_address(obj, offset >> PAGE_SHIFT),
> + node.start,
> + I915_CACHE_NONE,
> + 0);
> + wmb();
> + } else {
> + page_base += offset & PAGE_MASK;
> + }
> /* If we get a fault while copying data, then (presumably) our
> * source page isn't available. Return the error and we'll
> * retry in the slow path.
> */
> - if (fast_user_write(dev_priv->gtt.mappable, page_base,
> + if (fast_user_write(i915->gtt.mappable, page_base,
> page_offset, user_data, page_length)) {
> ret = -EFAULT;
> goto out_flush;
> @@ -821,7 +842,17 @@ i915_gem_gtt_pwrite_fast(struct drm_device *dev,
> out_flush:
> intel_fb_obj_flush(obj, false, ORIGIN_GTT);
> out_unpin:
> - i915_gem_object_ggtt_unpin(obj);
> + if (node.allocated) {
> + wmb();
> + i915->gtt.base.clear_range(&i915->gtt.base,
> + node.start, node.size,
> + true);
> + drm_mm_remove_node(&node);
> + i915_gem_object_unpin_pages(obj);
> + }
> + else {
> + i915_gem_object_ggtt_unpin(obj);
> + }
> out:
> return ret;
> }
> @@ -1086,7 +1117,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
> if (obj->tiling_mode == I915_TILING_NONE &&
> obj->base.write_domain != I915_GEM_DOMAIN_CPU &&
> cpu_write_needs_clflush(obj)) {
> - ret = i915_gem_gtt_pwrite_fast(dev, obj, args, file);
> + ret = i915_gem_gtt_pwrite_fast(dev_priv, obj, args, file);
> /* Note that the gtt paths might fail with non-page-backed user
> * pointers (e.g. gtt mappings when moving data between
> * textures). Fallback to the shmem path in that case. */
> --
> 1.9.1
>
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