[Linaro-mm-sig] Re: [PATCH net-next v3 3/4] selftests/net: ncdevmem: add -b option to set rx-buf-size on bind

On 06/12, Bobby Eshleman wrote:

From: Bobby Eshleman bobbyeshleman@meta.com

Add -b <bytes> to request a non-default niov size via NETDEV_A_DMABUF_RX_BUF_SIZE. When the value exceeds PAGE_SIZE, udmabuf_alloc() switches to an MFD_HUGETLB-backed memfd so each 2 MB hugepage produces one naturally-aligned sg entry.

Reject values > 2 MB up front: MFD_HUGETLB + udmabuf can only guarantee 2 MB per sg entry (one hugepage), so a larger rx_buf_size would fail the per-sg length/alignment check.

Add CONFIG_HUGETLBFS=y to drivers/net/hw/config so the new path is reachable in the CI kernels built for these tests.

Signed-off-by: Bobby Eshleman bobbyeshleman@meta.com

Acked-by: Stanislav Fomichev sdf@fomichev.me