From: Eric Dumazet <eric.dumazet@gmail.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>, bpf@vger.kernel.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"Jason Wang" <jasowang@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Björn Töpel" <bjorn@kernel.org>,
"Magnus Karlsson" <magnus.karlsson@intel.com>,
"Jonathan Lemon" <jonathan.lemon@gmail.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"Jesper Dangaard Brouer" <hawk@kernel.org>,
"John Fastabend" <john.fastabend@gmail.com>,
"Andrii Nakryiko" <andrii@kernel.org>,
"Martin KaFai Lau" <kafai@fb.com>,
"Song Liu" <songliubraving@fb.com>, "Yonghong Song" <yhs@fb.com>,
"KP Singh" <kpsingh@kernel.org>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next v3 3/3] xsk: build skb by page
Date: Thu, 21 Jan 2021 16:41:33 +0100 [thread overview]
Message-ID: <dcee4592-9fa9-adbb-55ca-58a962076e7a@gmail.com> (raw)
In-Reply-To: <340f1dfa40416dd966a56e08507daba82d633088.1611236588.git.xuanzhuo@linux.alibaba.com>
On 1/21/21 2:47 PM, Xuan Zhuo wrote:
> This patch is used to construct skb based on page to save memory copy
> overhead.
>
> This function is implemented based on IFF_TX_SKB_NO_LINEAR. Only the
> network card priv_flags supports IFF_TX_SKB_NO_LINEAR will use page to
> directly construct skb. If this feature is not supported, it is still
> necessary to copy data to construct skb.
>
> ---------------- Performance Testing ------------
>
> The test environment is Aliyun ECS server.
> Test cmd:
> ```
> xdpsock -i eth0 -t -S -s <msg size>
> ```
>
> Test result data:
>
> size 64 512 1024 1500
> copy 1916747 1775988 1600203 1440054
> page 1974058 1953655 1945463 1904478
> percent 3.0% 10.0% 21.58% 32.3%
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
> ---
> net/xdp/xsk.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 86 insertions(+), 18 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index 4a83117..38af7f1 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -430,6 +430,87 @@ static void xsk_destruct_skb(struct sk_buff *skb)
> sock_wfree(skb);
> }
>
> +static struct sk_buff *xsk_build_skb_zerocopy(struct xdp_sock *xs,
> + struct xdp_desc *desc)
> +{
> + u32 len, offset, copy, copied;
> + struct sk_buff *skb;
> + struct page *page;
> + void *buffer;
> + int err, i;
> + u64 addr;
> +
> + skb = sock_alloc_send_skb(&xs->sk, 0, 1, &err);
> + if (unlikely(!skb))
> + return ERR_PTR(err);
> +
> + addr = desc->addr;
> + len = desc->len;
> +
> + buffer = xsk_buff_raw_get_data(xs->pool, addr);
> + offset = offset_in_page(buffer);
> + addr = buffer - xs->pool->addrs;
> +
> + for (copied = 0, i = 0; copied < len; i++) {
> + page = xs->pool->umem->pgs[addr >> PAGE_SHIFT];
> +
> + get_page(page);
> +
> + copy = min_t(u32, PAGE_SIZE - offset, len - copied);
> +
> + skb_fill_page_desc(skb, i, page, offset, copy);
> +
> + copied += copy;
> + addr += copy;
> + offset = 0;
> + }
> +
> + skb->len += len;
> + skb->data_len += len;
> + skb->truesize += len;
This is not the truesize, unfortunately.
We need to account for the number of pages, not number of bytes.
> +
> + refcount_add(len, &xs->sk.sk_wmem_alloc);
> +
> + return skb;
> +}
> +
next prev parent reply other threads:[~2021-01-21 15:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 13:47 [PATCH bpf-next v3 0/3] xsk: build skb by page Xuan Zhuo
2021-01-21 13:47 ` [PATCH bpf-next v3 1/3] net: add priv_flags for allow tx skb without linear Xuan Zhuo
2021-01-21 15:13 ` Alexander Lobakin
2021-01-21 13:47 ` [PATCH bpf-next v3 2/3] virtio-net: support IFF_TX_SKB_NO_LINEAR Xuan Zhuo
2021-01-21 13:47 ` [PATCH bpf-next v3 3/3] xsk: build skb by page Xuan Zhuo
2021-01-21 15:17 ` Magnus Karlsson
2021-01-21 15:41 ` Eric Dumazet [this message]
2021-01-22 11:47 ` Alexander Lobakin
2021-01-22 11:55 ` Alexander Lobakin
2021-01-22 12:08 ` Alexander Lobakin
2021-01-22 12:18 ` Magnus Karlsson
2021-01-22 12:39 ` Alexander Lobakin
2021-01-22 12:55 ` Magnus Karlsson
[not found] <1611329789.3222687-1-xuanzhuo@linux.alibaba.com>
2021-01-22 16:24 ` Alexander Lobakin
[not found] <1611329955.4913929-2-xuanzhuo@linux.alibaba.com>
2021-01-22 17:26 ` Alexander Lobakin
2021-01-22 18:37 ` Magnus Karlsson
2021-01-22 18:45 ` Alexander Lobakin
[not found] ` <1611541335.3012564-1-xuanzhuo@linux.alibaba.com>
2021-01-25 7:44 ` Magnus Karlsson
[not found] ` <1611578136.5043845-1-xuanzhuo@linux.alibaba.com>
2021-01-25 13:16 ` Magnus Karlsson
[not found] ` <1611587242.9653594-2-xuanzhuo@linux.alibaba.com>
2021-01-26 7:34 ` Magnus Karlsson
[not found] <1611544243.8363645-1-xuanzhuo@linux.alibaba.com>
2021-01-25 13:25 ` Alexander Lobakin
[not found] <1611586627.1035807-1-xuanzhuo@linux.alibaba.com>
2021-01-25 15:07 ` Alexander Lobakin
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