[PATCH] drm/amdgpu: replace iova debugfs file with iomem (v2)

[Christian König]

Am 12.02.2018 um 17:40 schrieb Tom St Denis:
> On 09/02/18 01:44 PM, Christian König wrote:
>> Am 09.02.2018 um 19:19 schrieb Tom St Denis:
>>> On 09/02/18 01:17 PM, Christian König wrote:
>>>> Am 09.02.2018 um 18:28 schrieb Tom St Denis:
>>>>> On 09/02/18 12:27 PM, Tom St Denis wrote:
>>>>>> From: Christian König <ckoenig.leichtzumerken at gmail.com>
>>>>>
>>>>> Oops, I'll remove this from the commit message before pushing :-)
>>>>>
>>>>> I did give you credit below though.
>>>>
>>>> The patch before this one isn't merged yet because I'm still not 
>>>> sure if that works under all circumstances or not.
>>>>
>>>> Could you give it some extended testing? Especially if it work with 
>>>> eviction.
>>>
>>> I supposed there is a race on the kmap'ed memory which is why I 
>>> added a ptr check.  Not perfect but since it's a debugfs entry 
>>> probably better than it needs to be.
>>
>> I think you can drop that, kmap can only return NULL on 32bit systems 
>> when we ran out of vmap area and then you can basically call panic() 
>> as well.
>>
>> The question is if setting page->mapping during allocation has some 
>> undesired side effect.
>
>
> Haven't noticed anything with piglit or other FOSS GL games.
>
> Is there a specific test you'd like me to consider?

Try to restrict VRAM/GTT/memory in general and run something which needs 
a lot of CPU access to BOs. When it affects anything then the CPU page 
table unmap of BOs during eviction.

Christian.

>
> Tom