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

Michel Dänzer michel at
Tue Dec 19 10:37:15 UTC 2017

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 at>
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

Earthling Michel Dänzer               |     
Libre software enthusiast             |             Mesa and X developer

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