From f9e06c45cb28beb30a6a474952ead7da2b8940f3 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Thu, 15 Nov 2018 17:43:10 +0800 Subject: tuntap: free XDP dropped packets in a batch Thanks to the batched XDP buffs through msg_control. Instead of calling put_page() for each page which involves a atomic operation, let's batch them by record the last page that needs to be freed and its refcnt count and free them in a batch. Testpmd(virtio-user + vhost_net) + XDP_DROP shows 3.8% improvement. Before: 4.71Mpps After : 4.89Mpps Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a65779c6d72f..e90a7923a5f6 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -188,6 +188,11 @@ struct tun_file { struct xdp_rxq_info xdp_rxq; }; +struct tun_page { + struct page *page; + int count; +}; + struct tun_flow_entry { struct hlist_node hash_link; struct rcu_head rcu; @@ -2377,9 +2382,16 @@ static void tun_sock_write_space(struct sock *sk) kill_fasync(&tfile->fasync, SIGIO, POLL_OUT); } +static void tun_put_page(struct tun_page *tpage) +{ + if (tpage->page) + __page_frag_cache_drain(tpage->page, tpage->count); +} + static int tun_xdp_one(struct tun_struct *tun, struct tun_file *tfile, - struct xdp_buff *xdp, int *flush) + struct xdp_buff *xdp, int *flush, + struct tun_page *tpage) { struct tun_xdp_hdr *hdr = xdp->data_hard_start; struct virtio_net_hdr *gso = &hdr->gso; @@ -2390,6 +2402,7 @@ static int tun_xdp_one(struct tun_struct *tun, int buflen = hdr->buflen; int err = 0; bool skb_xdp = false; + struct page *page; xdp_prog = rcu_dereference(tun->xdp_prog); if (xdp_prog) { @@ -2416,7 +2429,14 @@ static int tun_xdp_one(struct tun_struct *tun, case XDP_PASS: break; default: - put_page(virt_to_head_page(xdp->data)); + page = virt_to_head_page(xdp->data); + if (tpage->page == page) { + ++tpage->count; + } else { + tun_put_page(tpage); + tpage->page = page; + tpage->count = 1; + } return 0; } } @@ -2480,6 +2500,7 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) return -EBADFD; if (ctl && (ctl->type == TUN_MSG_PTR)) { + struct tun_page tpage = {0}; int n = ctl->num; int flush = 0; @@ -2488,7 +2509,7 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) for (i = 0; i < n; i++) { xdp = &((struct xdp_buff *)ctl->ptr)[i]; - tun_xdp_one(tun, tfile, xdp, &flush); + tun_xdp_one(tun, tfile, xdp, &flush, &tpage); } if (flush) @@ -2497,6 +2518,8 @@ static int tun_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) rcu_read_unlock(); local_bh_enable(); + tun_put_page(&tpage); + ret = total_len; goto out; } -- cgit v1.2.1