168 строки
4.2 KiB
C
168 строки
4.2 KiB
C
/*
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* net busy poll support
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* Copyright(c) 2013 Intel Corporation.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Author: Eliezer Tamir
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*
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* Contact Information:
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* e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
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*/
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#ifndef _LINUX_NET_BUSY_POLL_H
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#define _LINUX_NET_BUSY_POLL_H
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#include <linux/netdevice.h>
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#include <linux/sched/clock.h>
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#include <linux/sched/signal.h>
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#include <net/ip.h>
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/* 0 - Reserved to indicate value not set
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* 1..NR_CPUS - Reserved for sender_cpu
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* NR_CPUS+1..~0 - Region available for NAPI IDs
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*/
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#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))
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#ifdef CONFIG_NET_RX_BUSY_POLL
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struct napi_struct;
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extern unsigned int sysctl_net_busy_read __read_mostly;
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extern unsigned int sysctl_net_busy_poll __read_mostly;
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static inline bool net_busy_loop_on(void)
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{
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return sysctl_net_busy_poll;
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}
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static inline bool sk_can_busy_loop(const struct sock *sk)
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{
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return sk->sk_ll_usec && !signal_pending(current);
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}
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bool sk_busy_loop_end(void *p, unsigned long start_time);
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void napi_busy_loop(unsigned int napi_id,
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bool (*loop_end)(void *, unsigned long),
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void *loop_end_arg);
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#else /* CONFIG_NET_RX_BUSY_POLL */
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static inline unsigned long net_busy_loop_on(void)
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{
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return 0;
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}
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static inline bool sk_can_busy_loop(struct sock *sk)
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{
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return false;
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}
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#endif /* CONFIG_NET_RX_BUSY_POLL */
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static inline unsigned long busy_loop_current_time(void)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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return (unsigned long)(local_clock() >> 10);
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#else
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return 0;
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#endif
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}
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/* in poll/select we use the global sysctl_net_ll_poll value */
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static inline bool busy_loop_timeout(unsigned long start_time)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
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if (bp_usec) {
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unsigned long end_time = start_time + bp_usec;
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unsigned long now = busy_loop_current_time();
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return time_after(now, end_time);
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}
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#endif
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return true;
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}
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static inline bool sk_busy_loop_timeout(struct sock *sk,
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unsigned long start_time)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
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if (bp_usec) {
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unsigned long end_time = start_time + bp_usec;
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unsigned long now = busy_loop_current_time();
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return time_after(now, end_time);
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}
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#endif
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return true;
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}
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static inline void sk_busy_loop(struct sock *sk, int nonblock)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
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if (napi_id >= MIN_NAPI_ID)
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napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
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#endif
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}
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static inline void sock_poll_busy_loop(struct socket *sock, __poll_t events)
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{
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if (sk_can_busy_loop(sock->sk) &&
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events && (events & POLL_BUSY_LOOP)) {
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/* once, only if requested by syscall */
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sk_busy_loop(sock->sk, 1);
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}
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}
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/* if this socket can poll_ll, tell the system call */
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static inline __poll_t sock_poll_busy_flag(struct socket *sock)
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{
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return sk_can_busy_loop(sock->sk) ? POLL_BUSY_LOOP : 0;
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}
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/* used in the NIC receive handler to mark the skb */
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static inline void skb_mark_napi_id(struct sk_buff *skb,
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struct napi_struct *napi)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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skb->napi_id = napi->napi_id;
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#endif
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}
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/* used in the protocol hanlder to propagate the napi_id to the socket */
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static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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sk->sk_napi_id = skb->napi_id;
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#endif
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sk_rx_queue_set(sk, skb);
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}
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/* variant used for unconnected sockets */
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static inline void sk_mark_napi_id_once(struct sock *sk,
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const struct sk_buff *skb)
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{
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#ifdef CONFIG_NET_RX_BUSY_POLL
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if (!sk->sk_napi_id)
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sk->sk_napi_id = skb->napi_id;
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#endif
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}
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#endif /* _LINUX_NET_BUSY_POLL_H */
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