Messages in this thread | | | Subject | Re: nouveau. swiotlb: coherent allocation failed for device 0000:01:00.0 size=2097152 | From | Christian König <> | Date | Tue, 19 Dec 2017 14:45:05 +0100 |
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Am 19.12.2017 um 11:39 schrieb Michel Dänzer: > 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.
Yeah, I think that is exactly what happens here.
We try to allocate a huge page, but fail and so fall back to using multiple 4k pages instead.
Going to send out a patch to suppress the warning.
Thanks for bisecting this, Christian.
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