Hi,
On Tue, 2022-05-03 at 19:13 +0000, Robert Beckett wrote:
> Internal gem objects will soon just be volatile system memory region
> objects.
> To enable this, create a separate dummy object creation function
> for gen6 ppgtt
It's not clear from the commit message why we need a special case for
this. Could you describe more in detail?
Thanks,
Thomas
>
> Signed-off-by: Robert Beckett <bob.beckett@xxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/gen6_ppgtt.c | 43
> ++++++++++++++++++++++++++--
> 1 file changed, 40 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
> b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
> index 1bb766c79dcb..f3b660cfeb7f 100644
> --- a/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen6_ppgtt.c
> @@ -372,6 +372,45 @@ static const struct drm_i915_gem_object_ops
> pd_dummy_obj_ops = {
> .put_pages = pd_dummy_obj_put_pages,
> };
>
> +static struct drm_i915_gem_object *
> +i915_gem_object_create_dummy(struct drm_i915_private *i915,
> phys_addr_t size)
> +{
> + static struct lock_class_key lock_class;
> + struct drm_i915_gem_object *obj;
> + unsigned int cache_level;
> +
> + GEM_BUG_ON(!size);
> + GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
> +
> + if (overflows_type(size, obj->base.size))
> + return ERR_PTR(-E2BIG);
> +
> + obj = i915_gem_object_alloc();
> + if (!obj)
> + return ERR_PTR(-ENOMEM);
> +
> + drm_gem_private_object_init(&i915->drm, &obj->base, size);
> + i915_gem_object_init(obj, &pd_dummy_obj_ops, &lock_class, 0);
> + obj->mem_flags |= I915_BO_FLAG_STRUCT_PAGE;
> +
> + /*
> + * Mark the object as volatile, such that the pages are
> marked as
> + * dontneed whilst they are still pinned. As soon as they are
> unpinned
> + * they are allowed to be reaped by the shrinker, and the
> caller is
> + * expected to repopulate - the contents of this object are
> only valid
> + * whilst active and pinned.
> + */
> + i915_gem_object_set_volatile(obj);
> +
> + obj->read_domains = I915_GEM_DOMAIN_CPU;
> + obj->write_domain = I915_GEM_DOMAIN_CPU;
> +
> + cache_level = HAS_LLC(i915) ? I915_CACHE_LLC :
> I915_CACHE_NONE;
> + i915_gem_object_set_cache_coherency(obj, cache_level);
> +
> + return obj;
> +}
> +
> static struct i915_page_directory *
> gen6_alloc_top_pd(struct gen6_ppgtt *ppgtt)
> {
> @@ -383,9 +422,7 @@ gen6_alloc_top_pd(struct gen6_ppgtt *ppgtt)
> if (unlikely(!pd))
> return ERR_PTR(-ENOMEM);
>
> - pd->pt.base = __i915_gem_object_create_internal(ppgtt-
> >base.vm.gt->i915,
> -
> &pd_dummy_obj_o
> ps,
> - I915_PDES *
> SZ_4K);
> + pd->pt.base = i915_gem_object_create_dummy(ppgtt->base.vm.gt-
> >i915, I915_PDES * SZ_4K);
> if (IS_ERR(pd->pt.base)) {
> err = PTR_ERR(pd->pt.base);
> pd->pt.base = NULL;
