Re: [PATCH] drm/amdgpu: check vm ready by evicting

Dear Qiang Yu,

Am 21.02.22 um 11:12 schrieb Qiang Yu:

Thank you for your patch. Reading the commit message summary, I have no idea what “check vm ready by evicting” means. Can you please rephrase it?

Workstation application ANSA/META get this error dmesg:

What version, and how can this be reproduced exactly? Just by starting the application?

[drm:amdgpu_gem_va_ioctl [amdgpu]] *ERROR* Couldn't update BO_VA (-16)

This is caused by:

1. create a 256MB buffer in invisible VRAM
2. CPU map the buffer and access it causes vm_fault and try to move it to visible VRAM
3. force visible VRAM space and traverse all VRAM bos to check if evicting this bo is valuable
4. when checking a VM bo (in invisible VRAM), amdgpu_vm_evictable() will set amdgpu_vm->evicting, but latter due to not in visible VRAM, won't really evict it so not add it to amdgpu_vm->evicted
5. before next CS to clear the amdgpu_vm->evicting, user VM ops ioctl will pass amdgpu_vm_ready() (check amdgpu_vm->evicted) but fail in amdgpu_vm_bo_update_mapping() (check amdgpu_vm->evicting) and get this error log

This error won't affect functionality as next CS will finish the waiting VM ops. But we'd better clear the error log by check the

s/check/checking/

evicting flag which really stop VM ops latter.

stop*s*?

Can you please elaborate. Christian’s and your discussions was quite long, so adding a summary, why this approach works and what possible regressions there are going to be might be warranted.

Kind regards,

Paul

Signed-off-by: Qiang Yu qiang.yu@amd.com

drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c index 37acd8911168..2cd9f1a2e5fa 100644 --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c @@ -770,11 +770,16 @@ int amdgpu_vm_validate_pt_bos(struct amdgpu_device *adev, struct amdgpu_vm *vm,

• Check if all VM PDs/PTs are ready for updates
• Returns:

• • True if eviction list is empty.

• • True if VM is not evicting.
  */ bool amdgpu_vm_ready(struct amdgpu_vm *vm) {

• return list_empty(&vm->evicted);

• bool ret;

• amdgpu_vm_eviction_lock(vm);

• ret = !vm->evicting;

• amdgpu_vm_eviction_unlock(vm);

• return ret; }

  /**