Re: nouveau. swiotlb: coherent allocation failed for device 0000:01:00.0 size=2097152

["Michel Dänzer" <michel@daenzer.net>]

On 2017-12-19 11:37 AM, Michel Dänzer wrote:
> On 2017-12-18 08:01 PM, Tobias Klausmann wrote:
>> On 12/18/17 7:06 PM, Mike Galbraith wrote:
>>> Greetings,
>>>
>>> Kernel bound workloads seem to trigger the below for whatever reason.
>>>   I only see this when beating up NFS.  There was a kworker wakeup
>>> latency issue, but with a bandaid applied to fix that up, I can still
>>> trigger this.
>>
>>
>> Hi,
>>
>> i have seen this one as well with my system, but i could not find an
>> easy way to trigger it for bisecting purpose. If you can trigger it
>> conveniently, a bisect would be nice!
> 
> I'm seeing this (with the amdgpu and radeon drivers) when restic takes a
> backup, creating memory pressure. I happen to have just finished
> bisecting, the result is:
> 
> 648bc3574716400acc06f99915815f80d9563783 is the first bad commit
> commit 648bc3574716400acc06f99915815f80d9563783
> Author: Christian König <christian.koenig@amd.com>
> Date:   Thu Jul 6 09:59:43 2017 +0200
> 
>     drm/ttm: add transparent huge page support for DMA allocations v2
> 
>     Try to allocate huge pages when it makes sense.
> 
>     v2: fix comment and use ifdef
> 
> 

BTW, I haven't noticed any bad effects other than the dmesg splats, so
maybe it's just noise about transient failures for which there is a
proper fallback in place.


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer