When to kmap PT BOs?

[Christian König]

Hi Felix,

ah, crap you are right.

I moved the kmap to amdgpu_vm_update_directories() because I thought 
that it would be cleaner to have that closer where it is used.

But that sounds like it doesn't work as intended. Going to revert that 
patch.

Thanks,
Christian.

Am 30.08.2018 um 00:30 schrieb Felix Kuehling:
> Hi,
>
> Currently PT BOs are kmapped in amdgpu_vm_update_directories. That
> means, to avoid kernel oopses after page table evictions, I need to call
> amdgpu_vm_update_directories before calling amdgpu_vm_bo_update.
>
> But amdgpu_vm_bo_update can also move PTs on the vm->relocated list
> during huge page handling. That means I also need to call
> amdgpu_vm_update_directories after amdgpu_vm_bo_update.
>
> I think a better solution is to move kmapping out of
> amdgpu_vm_update_directories. But I'm not sure what's the right place
> for it. Any suggestions? For a quick fix for kernel oopses after page
> table evictions in the ROCm 1.9 release I'll call
> amdgpu_vm_update_directories twice. If there are no new entries on the
> vm->relocated lists, the second call won't add much overhead anyway.
>
> Thanks,
>    Felix
>