> Subject: [PATCH] net/af_xdp: fix umem map size for zero copy
>
> The current calculation assumes that the mbufs are contiguous. However,
> this assumption is incorrect when the memory spans across a huge page.
> Correct to directly read the size from the mempool memory chunks.
>
> Signed-off-by: Frank Du <frank...@intel.com>
> ---
> drivers/net/af_xdp/rte_eth_af_xdp.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
> b/drivers/net/af_xdp/rte_eth_af_xdp.c
> index 268a130c49..cb95d17d13 100644
> --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
> +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
> @@ -1039,7 +1039,7 @@ eth_link_update(struct rte_eth_dev *dev
> __rte_unused,
> }
>
> #if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
> -static inline uintptr_t get_base_addr(struct rte_mempool *mp, uint64_t
> *align)
> +static inline uintptr_t get_memhdr_info(struct rte_mempool *mp, uint64_t
> *align, size_t *len)
> {
> struct rte_mempool_memhdr *memhdr;
> uintptr_t memhdr_addr, aligned_addr;
> @@ -1048,6 +1048,7 @@ static inline uintptr_t get_base_addr(struct
> rte_mempool *mp, uint64_t *align)
> memhdr_addr = (uintptr_t)memhdr->addr;
> aligned_addr = memhdr_addr & ~(getpagesize() - 1);
> *align = memhdr_addr - aligned_addr;
> + *len = memhdr->len;
>
> return aligned_addr;
> }
> @@ -1125,6 +1126,7 @@ xsk_umem_info *xdp_umem_configure(struct
> pmd_internals *internals,
> void *base_addr = NULL;
> struct rte_mempool *mb_pool = rxq->mb_pool;
> uint64_t umem_size, align = 0;
> + size_t len = 0;
>
> if (internals->shared_umem) {
> if (get_shared_umem(rxq, internals->if_name, &umem) < 0)
> @@ -1156,10 +1158,8 @@ xsk_umem_info *xdp_umem_configure(struct
> pmd_internals *internals,
> }
>
> umem->mb_pool = mb_pool;
> - base_addr = (void *)get_base_addr(mb_pool, &align);
> - umem_size = (uint64_t)mb_pool->populated_size *
> - (uint64_t)usr_config.frame_size +
> - align;
> + base_addr = (void *)get_memhdr_info(mb_pool, &align,
> &len);
> + umem_size = (uint64_t)len + align;
len is set to the length of the first memhdr of the mempool. There may be many
other memhdrs in the mempool. So I don't think this is the correct value to use
for calculating the entire umem size.
>
> ret = xsk_umem__create(&umem->umem, base_addr,
> umem_size,
> &rxq->fq, &rxq->cq, &usr_config);
> --
> 2.34.1
