When to kmap PT BOs?

[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

-- 
F e l i x   K u e h l i n g
PMTS Software Development Engineer | Linux Compute Kernel
1 Commerce Valley Dr. East, Markham, ON L3T 7X6 Canada
(O) +1(289)695-1597
   _     _   _   _____   _____
  / \   | \ / | |  _  \  \ _  |
 / A \  | \M/ | | |D) )  /|_| |
/_/ \_\ |_| |_| |_____/ |__/ \|   facebook.com/AMD | amd.com