Messages in this thread | | | Subject | Re: DMA-API: cacheline tracking ENOMEM, dma-debug disabled due to nouveau ? | From | Robin Murphy <> | Date | Thu, 15 Aug 2019 14:50:52 +0100 |
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On 15/08/2019 14:35, Christoph Hellwig wrote: > On Wed, Aug 14, 2019 at 07:49:27PM +0200, Daniel Vetter wrote: >> On Wed, Aug 14, 2019 at 04:50:33PM +0200, Corentin Labbe wrote: >>> Hello >>> >>> Since lot of release (at least since 4.19), I hit the following error message: >>> DMA-API: cacheline tracking ENOMEM, dma-debug disabled >>> >>> After hitting that, I try to check who is creating so many DMA mapping and see: >>> cat /sys/kernel/debug/dma-api/dump | cut -d' ' -f2 | sort | uniq -c >>> 6 ahci >>> 257 e1000e >>> 6 ehci-pci >>> 5891 nouveau >>> 24 uhci_hcd >>> >>> Does nouveau having this high number of DMA mapping is normal ? >> >> Yeah seems perfectly fine for a gpu. > > That is a lot and apparently overwhelm the dma-debug tracking. Robin > rewrote this code in Linux 4.21 to work a little better, so I'm curious > why this might have changes in 4.19, as dma-debug did not change at > all there.
FWIW, the cacheline tracking entries are a separate thing from the dma-debug entries that I rejigged - judging by those numbers there should still be plenty of free dma-debug entries, but for some reason it has failed to extend the radix tree :/
Robin.
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