[PATCH bpf-next v3 05/10] xsk: add busy-poll support for {recv,send}msg()
From: Björn Töpel <hidden>
Date: 2020-11-19 08:31:38
Also in:
bpf
Subsystem:
networking [general], the rest, xdp sockets (af_xdp) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Magnus Karlsson, Maciej Fijalkowski
From: Björn Töpel <redacted> Wire-up XDP socket busy-poll support for recvmsg() and sendmsg(). If the XDP socket prefers busy-polling, make sure that no wakeup/IPI is performed. Signed-off-by: Björn Töpel <redacted> --- net/xdp/xsk.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index bf0f5c34af6c..ecc4579e41ee 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c@@ -23,6 +23,7 @@ #include <linux/netdevice.h> #include <linux/rculist.h> #include <net/xdp_sock_drv.h> +#include <net/busy_poll.h> #include <net/xdp.h> #include "xsk_queue.h"
@@ -517,6 +518,17 @@ static int __xsk_sendmsg(struct sock *sk) return xs->zc ? xsk_zc_xmit(xs) : xsk_generic_xmit(sk); } +static bool xsk_no_wakeup(struct sock *sk) +{ +#ifdef CONFIG_NET_RX_BUSY_POLL + /* Prefer busy-polling, skip the wakeup. */ + return READ_ONCE(sk->sk_prefer_busy_poll) && READ_ONCE(sk->sk_ll_usec) && + READ_ONCE(sk->sk_napi_id) >= MIN_NAPI_ID; +#else + return false; +#endif +} + static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) { bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
@@ -529,6 +541,12 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len) if (unlikely(need_wait)) return -EOPNOTSUPP; + if (sk_can_busy_loop(sk)) + sk_busy_loop(sk, 1); /* only support non-blocking sockets */ + + if (xsk_no_wakeup(sk)) + return 0; + pool = xs->pool; if (pool->cached_need_wakeup & XDP_WAKEUP_TX) return __xsk_sendmsg(sk);
@@ -550,6 +568,12 @@ static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int fl if (unlikely(need_wait)) return -EOPNOTSUPP; + if (sk_can_busy_loop(sk)) + sk_busy_loop(sk, 1); /* only support non-blocking sockets */ + + if (xsk_no_wakeup(sk)) + return 0; + if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc) return xsk_wakeup(xs, XDP_WAKEUP_RX); return 0;
--
2.27.0