Bad rss-counter state from drm/ttm, drm/vmwgfx: Support huge TTM pagefaults

[Alex Xu (Hello71)]

Excerpts from Thomas Hellström (VMware)'s message of April 6, 2020 5:04 pm:
> Hi,
> 
> On 4/6/20 9:51 PM, Alex Xu (Hello71) wrote:
>> Using 314b658 with amdgpu, starting sway and firefox causes "BUG: Bad
>> rss-counter state" and "BUG: non-zero pgtables_bytes on freeing mm" to
>> start filling dmesg, and then closing programs causes more BUGs and
>> hangs, and then everything grinds to a halt (can't start more programs,
>> can't even reboot through systemd).
>>
>> Using master and reverting that branch up to that point fixes the
>> problem.
>>
>> I'm using a Ryzen 1600 and AMD Radeon RX 480 on an ASRock B450 Pro4
>> board with IOMMU enabled.
> 
> If you could try the attached patch, that'd be great!
> 
> Thanks,
> 
> Thomas
> 

Yeah, that works too. Kernel config sent off-list.

Regards,
Alex.