On Fri, Aug 16, 2019 at 4:31 PM Corentin Labbe clabbe.montjoie@gmail.com 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.
Note that it never go down and when I terminate my X session, it stays the same. So without any "real" GPU work, does it is still normal to have so many active mapping ?
Might just be the dma_alloc cache. It should go down under memory pressure I think. Otherwise might also be a leak.
For example, when doing some transfer, the ahci mapping number changes and then always go down to 6.
gpu drivers tend to cache everything, all the time ... -Daniel