Re: [PATCH] drm/amdkfd: don't add DOORBELL and MMIO BOs to validate list

[Lang Yu <Lang.Yu@amd.com>]

On 05/25/ , Christian König wrote:
> Am 25.05.22 um 10:43 schrieb Lang Yu:
> > DOORBELL and MMIO BOs never move once created.
> > No need to validate them after that.
> 
> Yeah, but you still need to make sure their page tables are up to date.
> 
> So this here might break horrible.

These BOs(and attachments) are validated when allocated and mapped.
Their page tables should be determined at this time. 

The kfd_bo_list is used to restore BOs after evictions.

Do you mean their page tabes could be changed? Thanks. 


> Christian.
> 
> > 
> > Signed-off-by: Lang Yu <Lang.Yu@amd.com>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 14 +++++++++-----
> >   1 file changed, 9 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > index 34ba9e776521..45de9cadd771 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
> > @@ -808,6 +808,10 @@ static void add_kgd_mem_to_kfd_bo_list(struct kgd_mem *mem,
> >   	struct ttm_validate_buffer *entry = &mem->validate_list;
> >   	struct amdgpu_bo *bo = mem->bo;
> > +	if (mem->alloc_flags & (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> > +				KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))
> > +		return;
> > +
> >   	INIT_LIST_HEAD(&entry->head);
> >   	entry->num_shared = 1;
> >   	entry->bo = &bo->tbo;
> > @@ -824,6 +828,10 @@ static void remove_kgd_mem_from_kfd_bo_list(struct kgd_mem *mem,
> >   {
> >   	struct ttm_validate_buffer *bo_list_entry;
> > +	if (mem->alloc_flags & (KFD_IOC_ALLOC_MEM_FLAGS_DOORBELL |
> > +				KFD_IOC_ALLOC_MEM_FLAGS_MMIO_REMAP))
> > +		return;
> > +
> >   	bo_list_entry = &mem->validate_list;
> >   	mutex_lock(&process_info->lock);
> >   	list_del(&bo_list_entry->head);
> > @@ -1649,7 +1657,6 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
> >   	unsigned long bo_size = mem->bo->tbo.base.size;
> >   	struct kfd_mem_attachment *entry, *tmp;
> >   	struct bo_vm_reservation_context ctx;
> > -	struct ttm_validate_buffer *bo_list_entry;
> >   	unsigned int mapped_to_gpu_memory;
> >   	int ret;
> >   	bool is_imported = false;
> > @@ -1677,10 +1684,7 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
> >   	}
> >   	/* Make sure restore workers don't access the BO any more */
> > -	bo_list_entry = &mem->validate_list;
> > -	mutex_lock(&process_info->lock);
> > -	list_del(&bo_list_entry->head);
> > -	mutex_unlock(&process_info->lock);
> > +	remove_kgd_mem_from_kfd_bo_list(mem, process_info);
> >   	/* No more MMU notifiers */
> >   	amdgpu_mn_unregister(mem->bo);
>