Re: [PATCH v3 3/4] drm/i915/ttm: add unmap_virtual callback

Thomas Hellström
2022-01-07T08:33:14Z

On 1/6/22 18:49, Matthew Auld wrote:
> Ensure we call ttm_bo_unmap_virtual when releasing the pages.
> Importantly this should now handle the ttm swapping case, and all other
> places that already call into i915_ttm_move_notify().
>
> v2: fix up the selftest
>
> Fixes: cf3e3e86d779 ("drm/i915: Use ttm mmap handling for ttm bo's.")
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>

Hm.

I guess we've been saved here previously by the fact that TTM calls
ttm_bo_unmap_virtual()
before calling the move callback.

Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>

> ---
> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 3 +++
> .../gpu/drm/i915/gem/i915_gem_object_types.h | 1 +
> drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 6 ++++++
> .../gpu/drm/i915/gem/selftests/i915_gem_mman.c | 18 ++++--------------
> 4 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index ee5ec0fd4807..5ac2506f4ee8 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -538,6 +538,9 @@ void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj)
> {
> struct i915_mmap_offset *mmo, *mn;
>
> + if (obj->ops->unmap_virtual)
> + obj->ops->unmap_virtual(obj);
> +
> spin_lock(&obj->mmo.lock);
> rbtree_postorder_for_each_entry_safe(mmo, mn,
> &obj->mmo.offsets, offset) {
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> index f9f7e44099fe..4b4829eb16c2 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
> @@ -67,6 +67,7 @@ struct drm_i915_gem_object_ops {
> int (*pwrite)(struct drm_i915_gem_object *obj,
> const struct drm_i915_gem_pwrite *arg);
> u64 (*mmap_offset)(struct drm_i915_gem_object *obj);
> + void (*unmap_virtual)(struct drm_i915_gem_object *obj);
>
> int (*dmabuf_export)(struct drm_i915_gem_object *obj);
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> index 8d61d4538a64..1530d9f0bc81 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
> @@ -950,6 +950,11 @@ static u64 i915_ttm_mmap_offset(struct drm_i915_gem_object *obj)
> return drm_vma_node_offset_addr(&obj->base.vma_node);
> }
>
> +static void i915_ttm_unmap_virtual(struct drm_i915_gem_object *obj)
> +{
> + ttm_bo_unmap_virtual(i915_gem_to_ttm(obj));
> +}
> +
> static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
> .name = "i915_gem_object_ttm",
> .flags = I915_GEM_OBJECT_IS_SHRINKABLE |
> @@ -965,6 +970,7 @@ static const struct drm_i915_gem_object_ops i915_gem_ttm_obj_ops = {
> .migrate = i915_ttm_migrate,
>
> .mmap_offset = i915_ttm_mmap_offset,
> + .unmap_virtual = i915_ttm_unmap_virtual,
> .mmap_ops = &vm_ops_ttm,
> };
>
> diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> index 743a098facf2..f61356b72b1c 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> @@ -1369,20 +1369,10 @@ static int __igt_mmap_revoke(struct drm_i915_private *i915,
> }
> }
>
> - if (!obj->ops->mmap_ops) {
> - err = check_absent(addr, obj->base.size);
> - if (err) {
> - pr_err("%s: was not absent\n", obj->mm.region->name);
> - goto out_unmap;
> - }
> - } else {
> - /* ttm allows access to evicted regions by design */
> -
> - err = check_present(addr, obj->base.size);
> - if (err) {
> - pr_err("%s: was not present\n", obj->mm.region->name);
> - goto out_unmap;
> - }
> + err = check_absent(addr, obj->base.size);
> + if (err) {
> + pr_err("%s: was not absent\n", obj->mm.region->name);
> + goto out_unmap;
> }
>