Re: generic DMA bypass flag v4
From: Jesper Dangaard Brouer <hidden>
Date: 2020-07-10 13:27:15
Also in:
linux-iommu, lkml
From: Jesper Dangaard Brouer <hidden>
Date: 2020-07-10 13:27:15
Also in:
linux-iommu, lkml
On Wed, 8 Jul 2020 17:24:44 +0200 Christoph Hellwig [off-list ref] wrote:
Note that as-is this breaks the XSK buffer pool, which unfortunately poked directly into DMA internals. A fix for that is already queued up in the netdev tree. Jesper and XDP gang: this should not regress any performance as the dma-direct calls are now inlined into the out of line DMA mapping calls. But if you can verify the performance numbers that would be greatly appreciated.
From a superficial review of the patches, they look okay to me. I don't have time to run a performance benchmark (before I go on vacation). I hoped Björn could test/benchmark this(?), given (as mentioned) this also affect XSK / AF_XDP performance. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer