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xsk: Add busy-poll support for {recv,send}msg()

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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 <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20201130185205.196029-6-bjorn.topel@gmail.com
This commit is contained in:
Björn Töpel 2020-11-30 19:52:00 +01:00 • committed by Daniel Borkmann
parent e392081837
commit a0731952d9
1 changed files with 24 additions and 0 deletions
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24
net/xdp/xsk.c
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@ -23,6 +23,7 @@
#include <linux/netdevice.h> #include <linux/netdevice.h>
#include <linux/rculist.h> #include <linux/rculist.h>
#include <net/xdp_sock_drv.h> #include <net/xdp_sock_drv.h>
#include <net/busy_poll.h>
#include <net/xdp.h> #include <net/xdp.h>
#include "xsk_queue.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); 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) static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
{ {
bool need_wait = !(m->msg_flags & MSG_DONTWAIT); 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)) if (unlikely(need_wait))
return -EOPNOTSUPP; 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; pool = xs->pool;
if (pool->cached_need_wakeup & XDP_WAKEUP_TX) if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
return __xsk_sendmsg(sk); 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)) if (unlikely(need_wait))
return -EOPNOTSUPP; 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) if (xs->pool->cached_need_wakeup & XDP_WAKEUP_RX && xs->zc)
return xsk_wakeup(xs, XDP_WAKEUP_RX); return xsk_wakeup(xs, XDP_WAKEUP_RX);
return 0; return 0;