Hi Niranjana,
On Tue, Sep 27, 2022 at 11:19:06PM -0700, Niranjana Vishwanathapura wrote:
> Add i915_vma_instance_persistent() to create persistent vmas.
> Persistent vmas will use i915_gtt_view to support partial binding.
>
> vma_lookup is tied to segment of the object instead of section
> of VA space. Hence, it do not support aliasing. ie., multiple
> mappings (at different VA) point to the same gtt_view of object.
> Skip vma_lookup for persistent vmas to support aliasing.
>
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@xxxxxxxxx>
> Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_vma.c | 39 ++++++++++++++++++++++++---
> drivers/gpu/drm/i915/i915_vma.h | 16 +++++++++--
> drivers/gpu/drm/i915/i915_vma_types.h | 7 +++++
> 3 files changed, 57 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
> index f17c09ead7d7..5839e1f55f00 100644
> --- a/drivers/gpu/drm/i915/i915_vma.c
> +++ b/drivers/gpu/drm/i915/i915_vma.c
> @@ -109,7 +109,8 @@ static void __i915_vma_retire(struct i915_active *ref)
> static struct i915_vma *
> vma_create(struct drm_i915_gem_object *obj,
> struct i915_address_space *vm,
> - const struct i915_gtt_view *view)
> + const struct i915_gtt_view *view,
> + bool skip_lookup_cache)
> {
> struct i915_vma *pos = ERR_PTR(-E2BIG);
> struct i915_vma *vma;
> @@ -196,6 +197,9 @@ vma_create(struct drm_i915_gem_object *obj,
> __set_bit(I915_VMA_GGTT_BIT, __i915_vma_flags(vma));
> }
>
> + if (skip_lookup_cache)
> + goto skip_rb_insert;
> +
> rb = NULL;
> p = &obj->vma.tree.rb_node;
> while (*p) {
> @@ -220,6 +224,7 @@ vma_create(struct drm_i915_gem_object *obj,
> rb_link_node(&vma->obj_node, rb, p);
> rb_insert_color(&vma->obj_node, &obj->vma.tree);
>
> +skip_rb_insert:
> if (i915_vma_is_ggtt(vma))
> /*
> * We put the GGTT vma at the start of the vma-list, followed
> @@ -299,7 +304,34 @@ i915_vma_instance(struct drm_i915_gem_object *obj,
>
> /* vma_create() will resolve the race if another creates the vma */
> if (unlikely(!vma))
> - vma = vma_create(obj, vm, view);
> + vma = vma_create(obj, vm, view, false);
> +
> + GEM_BUG_ON(!IS_ERR(vma) && i915_vma_compare(vma, vm, view));
> + return vma;
> +}
> +
> +/**
> + * i915_vma_create_persistent - create a persistent VMA
> + * @obj: parent &struct drm_i915_gem_object to be mapped
> + * @vm: address space in which the mapping is located
> + * @view: additional mapping requirements
> + *
> + * Creates a persistent vma.
> + *
> + * Returns the vma, or an error pointer.
> + */
> +struct i915_vma *
> +i915_vma_create_persistent(struct drm_i915_gem_object *obj,
> + struct i915_address_space *vm,
> + const struct i915_gtt_view *view)
> +{
> + struct i915_vma *vma;
> +
> + GEM_BUG_ON(!kref_read(&vm->ref));
> +
> + vma = vma_create(obj, vm, view, true);
> + if (!IS_ERR(vma))
> + i915_vma_set_persistent(vma);
>
> GEM_BUG_ON(!IS_ERR(vma) && i915_vma_compare(vma, vm, view));
> return vma;
> @@ -1666,7 +1698,8 @@ static void release_references(struct i915_vma *vma, struct intel_gt *gt,
>
> spin_lock(&obj->vma.lock);
> list_del(&vma->obj_link);
> - if (!RB_EMPTY_NODE(&vma->obj_node))
> + if (!i915_vma_is_persistent(vma) &&
> + !RB_EMPTY_NODE(&vma->obj_node))
> rb_erase(&vma->obj_node, &obj->vma.tree);
>
> spin_unlock(&obj->vma.lock);
> diff --git a/drivers/gpu/drm/i915/i915_vma.h b/drivers/gpu/drm/i915/i915_vma.h
> index aecd9c64486b..51e712de380a 100644
> --- a/drivers/gpu/drm/i915/i915_vma.h
> +++ b/drivers/gpu/drm/i915/i915_vma.h
> @@ -44,6 +44,10 @@ struct i915_vma *
> i915_vma_instance(struct drm_i915_gem_object *obj,
> struct i915_address_space *vm,
> const struct i915_gtt_view *view);
> +struct i915_vma *
> +i915_vma_create_persistent(struct drm_i915_gem_object *obj,
> + struct i915_address_space *vm,
> + const struct i915_gtt_view *view);
>
> void i915_vma_unpin_and_release(struct i915_vma **p_vma, unsigned int flags);
> #define I915_VMA_RELEASE_MAP BIT(0)
> @@ -138,6 +142,16 @@ static inline u32 i915_ggtt_pin_bias(struct i915_vma *vma)
> return i915_vm_to_ggtt(vma->vm)->pin_bias;
> }
>
> +static inline bool i915_vma_is_persistent(const struct i915_vma *vma)
> +{
> + return test_bit(I915_VMA_PERSISTENT_BIT, __i915_vma_flags(vma));
> +}
> +
> +static inline void i915_vma_set_persistent(struct i915_vma *vma)
> +{
> + set_bit(I915_VMA_PERSISTENT_BIT, __i915_vma_flags(vma));
> +}
> +
> static inline struct i915_vma *i915_vma_get(struct i915_vma *vma)
> {
> i915_gem_object_get(vma->obj);
> @@ -164,8 +178,6 @@ i915_vma_compare(struct i915_vma *vma,
> {
> ptrdiff_t cmp;
>
> - GEM_BUG_ON(view && !i915_is_ggtt_or_dpt(vm));
> -
> cmp = ptrdiff(vma->vm, vm);
> if (cmp)
> return cmp;
> diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h
> index ec0f6c9f57d0..2200f1f103ba 100644
> --- a/drivers/gpu/drm/i915/i915_vma_types.h
> +++ b/drivers/gpu/drm/i915/i915_vma_types.h
> @@ -264,6 +264,13 @@ struct i915_vma {
> #define I915_VMA_SCANOUT_BIT 17
> #define I915_VMA_SCANOUT ((int)BIT(I915_VMA_SCANOUT_BIT))
>
> +/**
> + * I915_VMA_PERSISTENT_BIT:
> + * The vma is persistent (created with VM_BIND call).
> + */
> +#define I915_VMA_PERSISTENT_BIT 19
> +#define I915_VMA_PERSISTENT ((int)BIT(I915_VMA_PERSISTENT_BIT))
> +
are we using I915_VMA_PERSISTENT anywhere?
Andi
> struct i915_active active;
>
> #define I915_VMA_PAGES_BIAS 24
> --
> 2.21.0.rc0.32.g243a4c7e27
