[PATCH 9/9] drm/amdgpu: WIP add IOCTL interface for per VM BOs

Christian König deathsimple at vodafone.de
Sat Aug 26 13:20:10 UTC 2017


Am 25.08.2017 um 23:31 schrieb Felix Kuehling:
> That's clever. I was scratching my head where the BOs were getting
> validated, just by sharing the VM reservation object. Until I carefully
> read your previous commit.

Yeah, didn't had time to properly comment on your last mail.

> In general, I find the VM code extremely frustrating and confusing to
> review. Too many lists of different things, and it's really hard to keep
> track of which list track what type of object, in which situation.
>
> For example, take struct amdgpu_vm:
>
> 	/* BOs who needs a validation */
> 	struct list_head	evicted;
>
> 	/* BOs moved, but not yet updated in the PT */
> 	struct list_head        moved;
>
> 	/* BO mappings freed, but not yet updated in the PT */
> 	struct list_head        freed;
>
> Three lists of BOs (according to the comments). But evicted and moved
> are lists of amdgpu_vm_bo_base, freed is a list of amdgpu_bo_va_mapping.
> moved and freed are used for tracking BOs mapped in the VM. I think
> moved may also track page table BOs, but I'm not sure. evicted is used
> only for tracking page table BOs.
>
> In patch #7 you add relocated to the mix. Now it gets really funny.
> What's the difference between relocated and evicted and moved?

Essentially nothing. I actually tried to merge them, but then realized 
that this would probably remove the ability to only update the 
directories and so most likely your KFD usage of that.

> It seems
> PT BOs can be on any of these lists. I think evicted means the BO needs
> to be validated. moved or relocated means it's been validated but its
> mappings must be updated. For PT BOs and mapped BOs that means different
> things, so it makes sense to have different lists for them. But I think
> PT BOs can also end up on the moved list when amdgpu_vm_bo_invalidate is
> called for a page table BO (through amdgpu_bo_move_notify). So I'm still
> confused.

amdgpu_vm_bo_invalidate() has logic to always put PDs and PTs on the 
relocated list and everything else on the moved list. So PDs/PTs should 
never end up on the moved list.

> I think this could be clarified with more descriptive names for the
> lists. If PT BOs and mapped BOs must be tracked separately that should
> be clear from the names.

That is a good idea, but in the long term I want to merge reloacted and 
moved list and then decide while walking the list what to do, but that 
is the next step I think.

Regards,
Christian.

>
> </rant>
>
> Regards,
>    Felix
>
>
> On 2017-08-25 05:38 AM, Christian König wrote:
>> From: Christian König <christian.koenig at amd.com>
>>
>> Add the IOCTL interface so that applications can allocate per VM BOs.
>>
>> Still WIP since not all corner cases are tested yet, but this reduces average
>> CS overhead for 10K BOs from 21ms down to 48us.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h       |  7 ++--
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c    |  2 +-
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c   | 59 ++++++++++++++++++++++---------
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c |  3 +-
>>   include/uapi/drm/amdgpu_drm.h             |  2 ++
>>   5 files changed, 51 insertions(+), 22 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index b1e817c..21cab36 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -457,9 +457,10 @@ struct amdgpu_sa_bo {
>>    */
>>   void amdgpu_gem_force_release(struct amdgpu_device *adev);
>>   int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
>> -				int alignment, u32 initial_domain,
>> -				u64 flags, bool kernel,
>> -				struct drm_gem_object **obj);
>> +			     int alignment, u32 initial_domain,
>> +			     u64 flags, bool kernel,
>> +			     struct reservation_object *resv,
>> +			     struct drm_gem_object **obj);
>>   
>>   int amdgpu_mode_dumb_create(struct drm_file *file_priv,
>>   			    struct drm_device *dev,
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> index 0e907ea..7256f83 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fb.c
>> @@ -144,7 +144,7 @@ static int amdgpufb_create_pinned_object(struct amdgpu_fbdev *rfbdev,
>>   				       AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
>>   				       AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS |
>>   				       AMDGPU_GEM_CREATE_VRAM_CLEARED,
>> -				       true, &gobj);
>> +				       true, NULL, &gobj);
>>   	if (ret) {
>>   		pr_err("failed to allocate framebuffer (%d)\n", aligned_size);
>>   		return -ENOMEM;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> index d028806..b8e8d67 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
>> @@ -44,11 +44,12 @@ void amdgpu_gem_object_free(struct drm_gem_object *gobj)
>>   }
>>   
>>   int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
>> -				int alignment, u32 initial_domain,
>> -				u64 flags, bool kernel,
>> -				struct drm_gem_object **obj)
>> +			     int alignment, u32 initial_domain,
>> +			     u64 flags, bool kernel,
>> +			     struct reservation_object *resv,
>> +			     struct drm_gem_object **obj)
>>   {
>> -	struct amdgpu_bo *robj;
>> +	struct amdgpu_bo *bo;
>>   	int r;
>>   
>>   	*obj = NULL;
>> @@ -59,7 +60,7 @@ int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
>>   
>>   retry:
>>   	r = amdgpu_bo_create(adev, size, alignment, kernel, initial_domain,
>> -			     flags, NULL, NULL, 0, &robj);
>> +			     flags, NULL, resv, 0, &bo);
>>   	if (r) {
>>   		if (r != -ERESTARTSYS) {
>>   			if (initial_domain == AMDGPU_GEM_DOMAIN_VRAM) {
>> @@ -71,7 +72,7 @@ int amdgpu_gem_object_create(struct amdgpu_device *adev, unsigned long size,
>>   		}
>>   		return r;
>>   	}
>> -	*obj = &robj->gem_base;
>> +	*obj = &bo->gem_base;
>>   
>>   	return 0;
>>   }
>> @@ -136,13 +137,14 @@ void amdgpu_gem_object_close(struct drm_gem_object *obj,
>>   	struct amdgpu_vm *vm = &fpriv->vm;
>>   
>>   	struct amdgpu_bo_list_entry vm_pd;
>> -	struct list_head list;
>> +	struct list_head list, duplicates;
>>   	struct ttm_validate_buffer tv;
>>   	struct ww_acquire_ctx ticket;
>>   	struct amdgpu_bo_va *bo_va;
>>   	int r;
>>   
>>   	INIT_LIST_HEAD(&list);
>> +	INIT_LIST_HEAD(&duplicates);
>>   
>>   	tv.bo = &bo->tbo;
>>   	tv.shared = true;
>> @@ -150,7 +152,7 @@ void amdgpu_gem_object_close(struct drm_gem_object *obj,
>>   
>>   	amdgpu_vm_get_pd_bo(vm, &list, &vm_pd);
>>   
>> -	r = ttm_eu_reserve_buffers(&ticket, &list, false, NULL);
>> +	r = ttm_eu_reserve_buffers(&ticket, &list, false, &duplicates);
>>   	if (r) {
>>   		dev_err(adev->dev, "leaking bo va because "
>>   			"we fail to reserve bo (%d)\n", r);
>> @@ -185,9 +187,12 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
>>   			    struct drm_file *filp)
>>   {
>>   	struct amdgpu_device *adev = dev->dev_private;
>> +	struct amdgpu_fpriv *fpriv = filp->driver_priv;
>> +	struct amdgpu_vm *vm = &fpriv->vm;
>>   	union drm_amdgpu_gem_create *args = data;
>>   	uint64_t flags = args->in.domain_flags;
>>   	uint64_t size = args->in.bo_size;
>> +	struct reservation_object *resv = NULL;
>>   	struct drm_gem_object *gobj;
>>   	uint32_t handle;
>>   	int r;
>> @@ -196,7 +201,8 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
>>   	if (flags & ~(AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
>>   		      AMDGPU_GEM_CREATE_NO_CPU_ACCESS |
>>   		      AMDGPU_GEM_CREATE_CPU_GTT_USWC |
>> -		      AMDGPU_GEM_CREATE_VRAM_CLEARED))
>> +		      AMDGPU_GEM_CREATE_VRAM_CLEARED |
>> +		      AMDGPU_GEM_CREATE_LOCAL))
>>   		return -EINVAL;
>>   
>>   	/* reject invalid gem domains */
>> @@ -223,9 +229,25 @@ int amdgpu_gem_create_ioctl(struct drm_device *dev, void *data,
>>   	}
>>   	size = roundup(size, PAGE_SIZE);
>>   
>> +	if (flags & AMDGPU_GEM_CREATE_LOCAL) {
>> +		r = amdgpu_bo_reserve(vm->root.base.bo, false);
>> +		if (r)
>> +			return r;
>> +
>> +		resv = vm->root.base.bo->tbo.resv;
>> +	}
>> +
>>   	r = amdgpu_gem_object_create(adev, size, args->in.alignment,
>>   				     (u32)(0xffffffff & args->in.domains),
>> -				     flags, false, &gobj);
>> +				     flags, false, resv, &gobj);
>> +	if (flags & AMDGPU_GEM_CREATE_LOCAL) {
>> +		if (!r) {
>> +			struct amdgpu_bo *abo = gem_to_amdgpu_bo(gobj);
>> +
>> +			abo->parent = amdgpu_bo_ref(vm->root.base.bo);
>> +		}
>> +		amdgpu_bo_unreserve(vm->root.base.bo);
>> +	}
>>   	if (r)
>>   		return r;
>>   
>> @@ -267,9 +289,8 @@ int amdgpu_gem_userptr_ioctl(struct drm_device *dev, void *data,
>>   	}
>>   
>>   	/* create a gem object to contain this object in */
>> -	r = amdgpu_gem_object_create(adev, args->size, 0,
>> -				     AMDGPU_GEM_DOMAIN_CPU, 0,
>> -				     0, &gobj);
>> +	r = amdgpu_gem_object_create(adev, args->size, 0, AMDGPU_GEM_DOMAIN_CPU,
>> +				     0, 0, NULL, &gobj);
>>   	if (r)
>>   		return r;
>>   
>> @@ -521,7 +542,7 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
>>   	struct amdgpu_bo_list_entry vm_pd;
>>   	struct ttm_validate_buffer tv;
>>   	struct ww_acquire_ctx ticket;
>> -	struct list_head list;
>> +	struct list_head list, duplicates;
>>   	uint64_t va_flags;
>>   	int r = 0;
>>   
>> @@ -557,6 +578,7 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
>>   	}
>>   
>>   	INIT_LIST_HEAD(&list);
>> +	INIT_LIST_HEAD(&duplicates);
>>   	if ((args->operation != AMDGPU_VA_OP_CLEAR) &&
>>   	    !(args->flags & AMDGPU_VM_PAGE_PRT)) {
>>   		gobj = drm_gem_object_lookup(filp, args->handle);
>> @@ -573,7 +595,7 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
>>   
>>   	amdgpu_vm_get_pd_bo(&fpriv->vm, &list, &vm_pd);
>>   
>> -	r = ttm_eu_reserve_buffers(&ticket, &list, true, NULL);
>> +	r = ttm_eu_reserve_buffers(&ticket, &list, true, &duplicates);
>>   	if (r)
>>   		goto error_unref;
>>   
>> @@ -639,6 +661,7 @@ int amdgpu_gem_va_ioctl(struct drm_device *dev, void *data,
>>   int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>>   			struct drm_file *filp)
>>   {
>> +	struct amdgpu_device *adev = dev->dev_private;
>>   	struct drm_amdgpu_gem_op *args = data;
>>   	struct drm_gem_object *gobj;
>>   	struct amdgpu_bo *robj;
>> @@ -686,6 +709,9 @@ int amdgpu_gem_op_ioctl(struct drm_device *dev, void *data,
>>   		if (robj->allowed_domains == AMDGPU_GEM_DOMAIN_VRAM)
>>   			robj->allowed_domains |= AMDGPU_GEM_DOMAIN_GTT;
>>   
>> +		if (robj->flags & AMDGPU_GEM_CREATE_LOCAL)
>> +			amdgpu_vm_bo_invalidate(adev, robj, true);
>> +
>>   		amdgpu_bo_unreserve(robj);
>>   		break;
>>   	default:
>> @@ -715,8 +741,7 @@ int amdgpu_mode_dumb_create(struct drm_file *file_priv,
>>   	r = amdgpu_gem_object_create(adev, args->size, 0,
>>   				     AMDGPU_GEM_DOMAIN_VRAM,
>>   				     AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED,
>> -				     ttm_bo_type_device,
>> -				     &gobj);
>> +				     false, NULL, &gobj);
>>   	if (r)
>>   		return -ENOMEM;
>>   
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> index 5b3f928..f407499 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_prime.c
>> @@ -136,7 +136,8 @@ struct dma_buf *amdgpu_gem_prime_export(struct drm_device *dev,
>>   {
>>   	struct amdgpu_bo *bo = gem_to_amdgpu_bo(gobj);
>>   
>> -	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm))
>> +	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
>> +	    bo->flags & AMDGPU_GEM_CREATE_LOCAL)
>>   		return ERR_PTR(-EPERM);
>>   
>>   	return drm_gem_prime_export(dev, gobj, flags);
>> diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
>> index d0ee739..05241a6 100644
>> --- a/include/uapi/drm/amdgpu_drm.h
>> +++ b/include/uapi/drm/amdgpu_drm.h
>> @@ -89,6 +89,8 @@ extern "C" {
>>   #define AMDGPU_GEM_CREATE_SHADOW		(1 << 4)
>>   /* Flag that allocating the BO should use linear VRAM */
>>   #define AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS	(1 << 5)
>> +/* Flag that BO is local in the VM */
>> +#define AMDGPU_GEM_CREATE_LOCAL			(1 << 6)
>>   
>>   struct drm_amdgpu_gem_create_in  {
>>   	/** the requested memory size */
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