[PATCH 00/13] shadow page table support

[Christian König]

Patch #1 looks like a fix to me, please add my rb and push ASAP.

You should separate such fixes from bugger sets, send out individually 
and maybe ping Alex to review and add them to his fixes branch.

Patch #2:
> +		amdgpu_ttm_placement_init(adev, &placement,
> +					  placements, AMDGPU_GEM_DOMAIN_GTT,
> +					  AMDGPU_GEM_CREATE_CPU_GTT_USWC);
> +
> +		r = amdgpu_bo_create_restricted(adev, size, byte_align, kernel,
> +						AMDGPU_GEM_DOMAIN_GTT,
> +						AMDGPU_GEM_CREATE_CPU_GTT_USWC,
> +						NULL, &placement,
> +						(*bo_ptr)->tbo.resv,
> +						&(*bo_ptr)->shadow);
> +		if (r)
> +			amdgpu_bo_unref(bo_ptr);

I think we should use the same reservation object as the parent BO here 
and add something like "(*bo_ptr)->shadow->parent = 
amdgpu_bo_ref(*bo_ptr);".

This way we can be sure that the shadow isn't freed before the BO.

> +	} else
> +		(*bo_ptr)->shadow = NULL;
 From the coding style when an "if" has {} the else part needs {} as 
well. But I think BOs are zero allocated anyway, so we can probably 
completely drop that.

> +		if (tbo == NULL)
Well that check is totally nonsense in the originally code as well. We 
should probably remove it.

Additional to that I would add something to amdgpu_cs_list_validate() to 
always validate the shadow when the real BO is validated.

Patch #3:
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index d415805..ae4608c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -875,6 +875,8 @@ struct amdgpu_ring {
>   struct amdgpu_vm_pt {
>   	struct amdgpu_bo_list_entry	entry;
>   	uint64_t			addr;
> +	struct amdgpu_bo_list_entry	entry_shadow;
> +	uint64_t			addr_shadow;
>   };
This becomes unnecessary when we use the same reservation object for the 
shadow and validate during CS and amdgpu_gem_va_update_vm().

Should reduce the CPU overhead of this significantly, cause otherwise we 
need to reserve and validate another BO for each page table.

For the remaining patches I would still use the approach of the common 
backup procedure as we discussed (with inverting the order for the VM 
BOs). Doubling all the page table updates clearly doesn't sound like a 
good idea to me.

Regards,
Christian.

Am 02.08.2016 um 09:48 schrieb Chunming Zhou:
> Since we cannot make sure VRAM is safe after gpu reset, page table backup
> is neccessary, shadow page table is sense way to recovery page talbe when
> gpu reset happens.
> We need to allocate GTT bo as the shadow of VRAM bo when creating page table,
> and make them same. After gpu reset, we will need to use SDMA to copy GTT bo
> content to VRAM bo, then page table will be recoveried.
>
> Chunming Zhou (13):
>    drm/amdgpu: irq resume should be immediately after gpu resume
>    drm/amdgpu: add shadow bo support
>    drm/amdgpu: set shadow flag for pd/pt bo
>    drm/amdgpu: update shadow pt bo while update pt
>    drm/amdgpu: update pd shadow while updating pd
>    drm/amdgpu: implement amdgpu_vm_recover_page_table_from_shadow
>    drm/amdgpu: link all vm clients
>    drm/amdgpu: add vm_list_lock
>    drm/amd: add block entity function
>    drm/amdgpu: recover page tables after gpu reset
>    drm/amd: wait neccessary dependency before running job
>    drm/amdgpu: add vm recover pt fence
>    drm/amdgpu: add backup condition for shadow page table
>
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h           |  15 ++
>   drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c        |   6 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c    |  33 +++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_job.c       |   5 +
>   drivers/gpu/drm/amd/amdgpu/amdgpu_object.c    |  36 ++++-
>   drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c        | 219 ++++++++++++++++++++++----
>   drivers/gpu/drm/amd/scheduler/gpu_scheduler.c |  30 +++-
>   drivers/gpu/drm/amd/scheduler/gpu_scheduler.h |   3 +
>   include/uapi/drm/amdgpu_drm.h                 |   2 +
>   9 files changed, 316 insertions(+), 33 deletions(-)
>