[PATCH] drm/amdgpu: Fix KFD oversubscription by tracking queues correctly

[Andres Rodriguez]

On 2017-07-13 03:35 PM, Felix Kuehling wrote:
> On 17-07-13 03:15 PM, Jay Cornwall wrote:
>> On Thu, Jul 13, 2017, at 13:36, Andres Rodriguez wrote:
>>> On 2017-07-12 02:26 PM, Jay Cornwall wrote:
>>>> The number of compute queues available to the KFD was erroneously
>>>> calculated as 64. Only the first MEC can execute compute queues and
>>>> it has 32 queue slots.
>>>>
>>>> This caused the oversubscription limit to be calculated incorrectly,
>>>> leading to a missing chained runlist command at the end of an
>>>> oversubscribed runlist.
>>>>
>>>> Change-Id: Ic4a139c04b8a6d025fbb831a0a67e98728bfe461
>>>> Signed-off-by: Jay Cornwall <Jay.Cornwall at amd.com>
>>>> ---
>>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 2 +-
>>>>    1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
>>>> index 7060daf..aa4006a 100644
>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
>>>> @@ -140,7 +140,7 @@ void amdgpu_amdkfd_device_init(struct amdgpu_device *adev)
>>>>    		/* According to linux/bitmap.h we shouldn't use bitmap_clear if
>>>>    		 * nbits is not compile time constant
>>>>    		 */
>>>> -		last_valid_bit = adev->gfx.mec.num_mec
>>>> +		last_valid_bit = 1 /* only first MEC can have compute queues */
>>> Hey Jay,
>>>
>>> Minor nitpick. We already have some similar resource patching in
>>> kgd2kfd_device_init(), and I think it would be good to keep all of these
>>> together.
>> OK. I see shared_resources.num_mec is set to 1 in kgd2kfd_device_init.
>> That's not very clear (the number of MECs doesn't change) and num_mec
>> doesn't appear to be used anywhere except in dead code in kfd_device.c.
>> That code also runs after the queue bitmap setup.
>>
>> How about I remove that field entirely?
> Yeah, that's fine with me.
> 

Good with me as well.