1 /* 2 * net busy poll support 3 * Copyright(c) 2013 Intel Corporation. 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms and conditions of the GNU General Public License, 7 * version 2, as published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 12 * more details. 13 * 14 * You should have received a copy of the GNU General Public License along with 15 * this program; if not, write to the Free Software Foundation, Inc., 16 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Author: Eliezer Tamir 19 * 20 * Contact Information: 21 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net> 22 */ 23 24 #ifndef _LINUX_NET_BUSY_POLL_H 25 #define _LINUX_NET_BUSY_POLL_H 26 27 #include <linux/netdevice.h> 28 #include <linux/sched/clock.h> 29 #include <linux/sched/signal.h> 30 #include <net/ip.h> 31 32 /* 0 - Reserved to indicate value not set 33 * 1..NR_CPUS - Reserved for sender_cpu 34 * NR_CPUS+1..~0 - Region available for NAPI IDs 35 */ 36 #define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1)) 37 38 #ifdef CONFIG_NET_RX_BUSY_POLL 39 40 struct napi_struct; 41 extern unsigned int sysctl_net_busy_read __read_mostly; 42 extern unsigned int sysctl_net_busy_poll __read_mostly; 43 44 static inline bool net_busy_loop_on(void) 45 { 46 return sysctl_net_busy_poll; 47 } 48 49 static inline bool sk_can_busy_loop(const struct sock *sk) 50 { 51 return sk->sk_ll_usec && !signal_pending(current); 52 } 53 54 bool sk_busy_loop_end(void *p, unsigned long start_time); 55 56 void napi_busy_loop(unsigned int napi_id, 57 bool (*loop_end)(void *, unsigned long), 58 void *loop_end_arg); 59 60 #else /* CONFIG_NET_RX_BUSY_POLL */ 61 static inline unsigned long net_busy_loop_on(void) 62 { 63 return 0; 64 } 65 66 static inline bool sk_can_busy_loop(struct sock *sk) 67 { 68 return false; 69 } 70 71 #endif /* CONFIG_NET_RX_BUSY_POLL */ 72 73 static inline unsigned long busy_loop_current_time(void) 74 { 75 #ifdef CONFIG_NET_RX_BUSY_POLL 76 return (unsigned long)(local_clock() >> 10); 77 #else 78 return 0; 79 #endif 80 } 81 82 /* in poll/select we use the global sysctl_net_ll_poll value */ 83 static inline bool busy_loop_timeout(unsigned long start_time) 84 { 85 #ifdef CONFIG_NET_RX_BUSY_POLL 86 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll); 87 88 if (bp_usec) { 89 unsigned long end_time = start_time + bp_usec; 90 unsigned long now = busy_loop_current_time(); 91 92 return time_after(now, end_time); 93 } 94 #endif 95 return true; 96 } 97 98 static inline bool sk_busy_loop_timeout(struct sock *sk, 99 unsigned long start_time) 100 { 101 #ifdef CONFIG_NET_RX_BUSY_POLL 102 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec); 103 104 if (bp_usec) { 105 unsigned long end_time = start_time + bp_usec; 106 unsigned long now = busy_loop_current_time(); 107 108 return time_after(now, end_time); 109 } 110 #endif 111 return true; 112 } 113 114 static inline void sk_busy_loop(struct sock *sk, int nonblock) 115 { 116 #ifdef CONFIG_NET_RX_BUSY_POLL 117 unsigned int napi_id = READ_ONCE(sk->sk_napi_id); 118 119 if (napi_id >= MIN_NAPI_ID) 120 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk); 121 #endif 122 } 123 124 static inline void sock_poll_busy_loop(struct socket *sock, __poll_t events) 125 { 126 if (sk_can_busy_loop(sock->sk) && 127 events && (events & POLL_BUSY_LOOP)) { 128 /* once, only if requested by syscall */ 129 sk_busy_loop(sock->sk, 1); 130 } 131 } 132 133 /* if this socket can poll_ll, tell the system call */ 134 static inline __poll_t sock_poll_busy_flag(struct socket *sock) 135 { 136 return sk_can_busy_loop(sock->sk) ? POLL_BUSY_LOOP : 0; 137 } 138 139 /* used in the NIC receive handler to mark the skb */ 140 static inline void skb_mark_napi_id(struct sk_buff *skb, 141 struct napi_struct *napi) 142 { 143 #ifdef CONFIG_NET_RX_BUSY_POLL 144 skb->napi_id = napi->napi_id; 145 #endif 146 } 147 148 /* used in the protocol hanlder to propagate the napi_id to the socket */ 149 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb) 150 { 151 #ifdef CONFIG_NET_RX_BUSY_POLL 152 sk->sk_napi_id = skb->napi_id; 153 #endif 154 } 155 156 /* variant used for unconnected sockets */ 157 static inline void sk_mark_napi_id_once(struct sock *sk, 158 const struct sk_buff *skb) 159 { 160 #ifdef CONFIG_NET_RX_BUSY_POLL 161 if (!sk->sk_napi_id) 162 sk->sk_napi_id = skb->napi_id; 163 #endif 164 } 165 166 #endif /* _LINUX_NET_BUSY_POLL_H */ 167