Re: [Intel-gfx] [RFC PATCH v3 05/17] drm/i915: Support for VM private BOs

Niranjana Vishwanathapura
2022-08-31T06:14:20Z

On Sat, Aug 27, 2022 at 09:43:51PM +0200, Andi Shyti wrote:
>From: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
>
>Each VM creates a root_obj and shares it with all of its private objects
>to use it as dma_resv object. This has a performance advantage as it
>requires a single dma_resv object update for all private BOs vs list of
>dma_resv objects update for shared BOs, in the execbuf path.
>
>Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
>Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
>Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com>
>---
> drivers/gpu/drm/i915/gem/i915_gem_object_types.h | 3 +++
> drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c | 9 +++++++++
> drivers/gpu/drm/i915/gt/intel_gtt.c | 4 ++++
> drivers/gpu/drm/i915/gt/intel_gtt.h | 2 ++
> drivers/gpu/drm/i915/i915_vma.c | 1 +
> drivers/gpu/drm/i915/i915_vma_types.h | 2 ++
> 6 files changed, 21 insertions(+)
>
>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 9f6b14ec189a2..46308dcf39e99 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
>@@ -241,6 +241,9 @@ struct drm_i915_gem_object {
>
> const struct drm_i915_gem_object_ops *ops;
>
>+ /* For VM private BO, points to root_obj in VM. NULL otherwise */
>+ struct drm_i915_gem_object *priv_root;
>+
> struct {
> /**
> * @vma.lock: protect the list/tree of vmas
>diff --git a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>index dadd1d4b1761b..9ff929f187cfd 100644
>--- a/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>+++ b/drivers/gpu/drm/i915/gem/i915_gem_vm_bind_object.c
>@@ -93,6 +93,7 @@ void i915_gem_vm_bind_remove(struct i915_vma *vma, bool release_obj)
>
> if (!list_empty(&vma->vm_bind_link)) {
> list_del_init(&vma->vm_bind_link);
>+ list_del_init(&vma->non_priv_vm_bind_link);
> i915_vm_bind_it_remove(vma, &vma->vm->va);
>
> /* Release object */
>@@ -219,6 +220,11 @@ static int i915_gem_vm_bind_obj(struct i915_address_space *vm,
> goto put_obj;
> }
>
>+ if (obj->priv_root && obj->priv_root != vm->root_obj) {
>+ ret = -EINVAL;
>+ goto put_obj;
>+ }
>+
> ret = mutex_lock_interruptible(&vm->vm_bind_lock);
> if (ret)
> goto put_obj;
>@@ -244,6 +250,9 @@ static int i915_gem_vm_bind_obj(struct i915_address_space *vm,
>
> list_add_tail(&vma->vm_bind_link, &vm->vm_bound_list);
> i915_vm_bind_it_insert(vma, &vm->va);
>+ if (!obj->priv_root)
>+ list_add_tail(&vma->non_priv_vm_bind_link,
>+ &vm->non_priv_vm_bind_list);
>
> out_ww:
> if (ret == -EDEADLK) {
>diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.c b/drivers/gpu/drm/i915/gt/intel_gtt.c
>index cb188377b7bd9..c4f75826213ae 100644
>--- a/drivers/gpu/drm/i915/gt/intel_gtt.c
>+++ b/drivers/gpu/drm/i915/gt/intel_gtt.c
>@@ -177,6 +177,7 @@ int i915_vm_lock_objects(struct i915_address_space *vm,
> void i915_address_space_fini(struct i915_address_space *vm)
> {
> drm_mm_takedown(&vm->mm);
>+ i915_gem_object_put(vm->root_obj);
> GEM_BUG_ON(!RB_EMPTY_ROOT(&vm->va.rb_root));
> mutex_destroy(&vm->vm_bind_lock);
> }
>@@ -292,6 +293,9 @@ void i915_address_space_init(struct i915_address_space *vm, int subclass)
> INIT_LIST_HEAD(&vm->vm_bind_list);
> INIT_LIST_HEAD(&vm->vm_bound_list);
> mutex_init(&vm->vm_bind_lock);
>+ INIT_LIST_HEAD(&vm->non_priv_vm_bind_list);
>+ vm->root_obj = i915_gem_object_create_internal(vm->i915, PAGE_SIZE);
>+ GEM_BUG_ON(IS_ERR(vm->root_obj));
> }
>
> void *__px_vaddr(struct drm_i915_gem_object *p)
>diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
>index 06a259475816b..9a2665e4ec2e5 100644
>--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
>+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
>@@ -267,6 +267,8 @@ struct i915_address_space {
> struct list_head vm_bound_list;
> /* @va: tree of persistent vmas */
> struct rb_root_cached va;
>+ struct list_head non_priv_vm_bind_list;
>+ struct drm_i915_gem_object *root_obj;
>
> /* Global GTT */
> bool is_ggtt:1;
>diff --git a/drivers/gpu/drm/i915/i915_vma.c b/drivers/gpu/drm/i915/i915_vma.c
>index 092ae4309d8a1..239346e0c07f2 100644
>--- a/drivers/gpu/drm/i915/i915_vma.c
>+++ b/drivers/gpu/drm/i915/i915_vma.c
>@@ -236,6 +236,7 @@ vma_create(struct drm_i915_gem_object *obj,
> mutex_unlock(&vm->mutex);
>
> INIT_LIST_HEAD(&vma->vm_bind_link);
>+ INIT_LIST_HEAD(&vma->non_priv_vm_bind_link);
> return vma;
>
> err_unlock:
>diff --git a/drivers/gpu/drm/i915/i915_vma_types.h b/drivers/gpu/drm/i915/i915_vma_types.h
>index f746fecae85ed..de5534d518cdd 100644
>--- a/drivers/gpu/drm/i915/i915_vma_types.h
>+++ b/drivers/gpu/drm/i915/i915_vma_types.h
>@@ -291,6 +291,8 @@ struct i915_vma {
>
> /** @vm_bind_link: node for the vm_bind related lists of vm */
> struct list_head vm_bind_link;
>+ /* @non_priv_vm_bind_link: Link in non-private persistent VMA list */
>+ struct list_head non_priv_vm_bind_link;
>
> /** Interval tree structures for persistent vma */
>

I am not seeing the upai part to allow user to specify an object as private.

Niranjana

>--
>2.34.1
>