On 2023/4/23 2:54, Lorenzo Bianconi wrote:
> struct veth_priv {
> @@ -727,17 +729,20 @@ static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
> goto drop;
>
> /* Allocate skb head */
> - page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
> + page = page_pool_dev_alloc_pages(rq->page_pool);
> if (!page)
> goto drop;
>
> nskb = build_skb(page_address(page), PAGE_SIZE);
If page pool is used with PP_FLAG_PAGE_FRAG, maybe there is some additional
improvement for the MTU 1500B case, it seem a 4K page is able to hold two skb.
And we can reduce the memory usage too, which is a significant saving if page
size is 64K.
> if (!nskb) {
> - put_page(page);
> + page_pool_put_full_page(rq->page_pool, page, true);
> goto drop;
> }
>
> skb_reserve(nskb, VETH_XDP_HEADROOM);
> + skb_copy_header(nskb, skb);
> + skb_mark_for_recycle(nskb);
> +
> size = min_t(u32, skb->len, max_head_size);
> if (skb_copy_bits(skb, 0, nskb->data, size)) {
> consume_skb(nskb);
> @@ -745,7 +750,6 @@ static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
> }
> skb_put(nskb, size);
>
> - skb_copy_header(nskb, skb);
> head_off = skb_headroom(nskb) - skb_headroom(skb);
> skb_headers_offset_update(nskb, head_off);
>
> @@ -754,7 +758,7 @@ static int veth_convert_skb_to_xdp_buff(struct veth_rq *rq,
> len = skb->len - off;
>
> for (i = 0; i < MAX_SKB_FRAGS && off < skb->len; i++) {
> - page = alloc_page(GFP_ATOMIC | __GFP_NOWARN);
> + page = page_pool_dev_alloc_pages(rq->page_pool);
> if (!page) {
> consume_skb(nskb);
> goto drop;
> @@ -1002,11 +1006,37 @@ static int veth_poll(struct napi_struct *napi, int budget)
> return done;
> }
>
> +static int veth_create_page_pool(struct veth_rq *rq)
> +{
> + struct page_pool_params pp_params = {
> + .order = 0,
> + .pool_size = VETH_RING_SIZE,
It seems better to allocate different poo_size according to
the mtu, so that the best proformance is achiced using the
least memory?
