Am 03.01.2018 um 12:57 schrieb Zhou, David(ChunMing):
>>>> + else if (reservation_object_trylock(resv))
>>>> + clear = false;
this will effect bo in bo list，wont it?
Ah, now I get what you mean.
Yeah, that should be fixed or otherwise it will completely disable
vm_debug support.
Going to send a patch,
Christian.
发自坚果 Pro
Koenig, Christian <[email protected]> 于 2018年1月3日
下午6:47写道：
Am 03.01.2018 um 11:43 schrieb Chunming Zhou:
>
>
> On 2018年01月03日 17:25, Christian König wrote:
>> Am 03.01.2018 um 09:10 schrieb Zhou, David(ChunMing):
>>>
>>> On 2018年01月02日 22:47, Christian König wrote:
>>>> Try to lock moved BOs if it's successful we can update the
>>>> PTEs directly to the new location.
>>>>
>>>> v2: rebase
>>>>
>>>> Signed-off-by: Christian König <[email protected]>
>>>> ---
>>>> drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 15 ++++++++++++++-
>>>> 1 file changed, 14 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> index 3632c69f1814..c1c5ccdee783 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
>>>> @@ -1697,18 +1697,31 @@ int amdgpu_vm_handle_moved(struct
>>>> amdgpu_device *adev,
>>>> spin_lock(&vm->status_lock);
>>>> while (!list_empty(&vm->moved)) {
>>>> struct amdgpu_bo_va *bo_va;
>>>> + struct reservation_object *resv;
>>>> bo_va = list_first_entry(&vm->moved,
>>>> struct amdgpu_bo_va, base.vm_status);
>>>> spin_unlock(&vm->status_lock);
>>>> + resv = bo_va->base.bo->tbo.resv;
>>>> +
>>>> /* Per VM BOs never need to bo cleared in the page
>>>> tables */
>>> This reminders us Per-VM-BOs need to cleared as well after we allow to
>>> evict/swap out per-vm-bos.
>>
>> Actually they don't. The page tables only need to be valid during CS.
>>
>> So what happens is that the per VM-BOs are validated in right before
>> we call amdgpu_vm_handle_moved().
> Yeah, agree it for per-vm-bo situation after I checked all adding
> moved list cases:
> 1. validate pt bos
> 2. bo invalidate
> 3. insert_map for per-vm-bo
> item #1 and #3 both are per-vm-bo, they are already validated before
> handle_moved().
>
> For item #2, there are three places to call it:
> a. amdgpu_bo_vm_update_pte in CS for amdgpu_vm_debug
> b. amdgpu_gem_op_ioctl, but it is for evicted list, nothing with moved
> list.
> c. amdgpu_bo_move_notify when bo validate.
>
> For c case, your optimization is valid, we don't need clear for
> validate bo.
> But for a case, yours will break amdgpu_vm_debug functionality.
>
> Right?
Interesting point, but no that should be handled as well.
The vm_debug handling is only for the BOs on the BO-list. E.g. per VM
BOs are never handled here.
Regards,
Christian.
>
> Regards,
> David Zhou
>
>>
>> Regards,
>> Christian.
>>
>>>
>>> Regards,
>>> David Zhou
>>>> - clear = bo_va->base.bo->tbo.resv !=
>>>> vm->root.base.bo->tbo.resv;
>>>> + if (resv == vm->root.base.bo->tbo.resv)
>>>> + clear = false;
>>>> + /* Try to reserve the BO to avoid clearing its ptes */
>>>> + else if (reservation_object_trylock(resv))
>>>> + clear = false;
>>>> + /* Somebody else is using the BO right now */
>>>> + else
>>>> + clear = true;
>>>> r = amdgpu_vm_bo_update(adev, bo_va, clear);
>>>> if (r)
>>>> return r;
>>>> + if (!clear && resv != vm->root.base.bo->tbo.resv)
>>>> + reservation_object_unlock(resv);
>>>> +
>>>> spin_lock(&vm->status_lock);
>>>> }
>>>> spin_unlock(&vm->status_lock);
>>
>
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