On Tue, Nov 24, 2020 at 09:25:06AM +0000, Kalra, Ashish wrote: > But what will be the criteria to figure out this percentage? > > As I mentioned earlier, this can be made as complicated as possible by > adding all kind of heuristics but without any predictable performance > gain. > > Or it can be kept simple by using a static percentage value.
Yes, static percentage number based on the guest memory. X% of the guest memory is used for SWIOTLB. Since you use sev_active(), it means the size computation is done in the guest so that SWIOTLB size is per-guest. Yes? If so, you can simply take, say, 5% of the guest memory's size and use that for SWIOTLB buffers. Or 6 or X or whatever. Makes sense? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu