1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * net busy poll support 4 * Copyright(c) 2013 Intel Corporation. 5 * 6 * Author: Eliezer Tamir 7 * 8 * Contact Information: 9 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net> 10 */ 11 12 #ifndef _LINUX_NET_BUSY_POLL_H 13 #define _LINUX_NET_BUSY_POLL_H 14 15 #include <linux/netdevice.h> 16 #include <linux/sched/clock.h> 17 #include <linux/sched/signal.h> 18 #include <net/ip.h> 19 #include <net/xdp.h> 20 21 /* 0 - Reserved to indicate value not set 22 * 1..NR_CPUS - Reserved for sender_cpu 23 * NR_CPUS+1..~0 - Region available for NAPI IDs 24 */ 25 #define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1)) 26 27 #define BUSY_POLL_BUDGET 8 28 29 #ifdef CONFIG_NET_RX_BUSY_POLL 30 31 struct napi_struct; 32 extern unsigned int sysctl_net_busy_read __read_mostly; 33 extern unsigned int sysctl_net_busy_poll __read_mostly; 34 35 static inline bool net_busy_loop_on(void) 36 { 37 return READ_ONCE(sysctl_net_busy_poll); 38 } 39 40 static inline bool sk_can_busy_loop(const struct sock *sk) 41 { 42 return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current); 43 } 44 45 bool sk_busy_loop_end(void *p, unsigned long start_time); 46 47 void napi_busy_loop(unsigned int napi_id, 48 bool (*loop_end)(void *, unsigned long), 49 void *loop_end_arg, bool prefer_busy_poll, u16 budget); 50 51 void napi_busy_loop_rcu(unsigned int napi_id, 52 bool (*loop_end)(void *, unsigned long), 53 void *loop_end_arg, bool prefer_busy_poll, u16 budget); 54 55 #else /* CONFIG_NET_RX_BUSY_POLL */ 56 static inline unsigned long net_busy_loop_on(void) 57 { 58 return 0; 59 } 60 61 static inline bool sk_can_busy_loop(struct sock *sk) 62 { 63 return false; 64 } 65 66 #endif /* CONFIG_NET_RX_BUSY_POLL */ 67 68 static inline unsigned long busy_loop_current_time(void) 69 { 70 #ifdef CONFIG_NET_RX_BUSY_POLL 71 return (unsigned long)(local_clock() >> 10); 72 #else 73 return 0; 74 #endif 75 } 76 77 /* in poll/select we use the global sysctl_net_ll_poll value */ 78 static inline bool busy_loop_timeout(unsigned long start_time) 79 { 80 #ifdef CONFIG_NET_RX_BUSY_POLL 81 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll); 82 83 if (bp_usec) { 84 unsigned long end_time = start_time + bp_usec; 85 unsigned long now = busy_loop_current_time(); 86 87 return time_after(now, end_time); 88 } 89 #endif 90 return true; 91 } 92 93 static inline bool sk_busy_loop_timeout(struct sock *sk, 94 unsigned long start_time) 95 { 96 #ifdef CONFIG_NET_RX_BUSY_POLL 97 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec); 98 99 if (bp_usec) { 100 unsigned long end_time = start_time + bp_usec; 101 unsigned long now = busy_loop_current_time(); 102 103 return time_after(now, end_time); 104 } 105 #endif 106 return true; 107 } 108 109 static inline void sk_busy_loop(struct sock *sk, int nonblock) 110 { 111 #ifdef CONFIG_NET_RX_BUSY_POLL 112 unsigned int napi_id = READ_ONCE(sk->sk_napi_id); 113 114 if (napi_id >= MIN_NAPI_ID) 115 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk, 116 READ_ONCE(sk->sk_prefer_busy_poll), 117 READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET); 118 #endif 119 } 120 121 /* used in the NIC receive handler to mark the skb */ 122 static inline void skb_mark_napi_id(struct sk_buff *skb, 123 struct napi_struct *napi) 124 { 125 #ifdef CONFIG_NET_RX_BUSY_POLL 126 /* If the skb was already marked with a valid NAPI ID, avoid overwriting 127 * it. 128 */ 129 if (skb->napi_id < MIN_NAPI_ID) 130 skb->napi_id = napi->napi_id; 131 #endif 132 } 133 134 /* used in the protocol hanlder to propagate the napi_id to the socket */ 135 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb) 136 { 137 #ifdef CONFIG_NET_RX_BUSY_POLL 138 if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id)) 139 WRITE_ONCE(sk->sk_napi_id, skb->napi_id); 140 #endif 141 sk_rx_queue_update(sk, skb); 142 } 143 144 /* Variant of sk_mark_napi_id() for passive flow setup, 145 * as sk->sk_napi_id and sk->sk_rx_queue_mapping content 146 * needs to be set. 147 */ 148 static inline void sk_mark_napi_id_set(struct sock *sk, 149 const struct sk_buff *skb) 150 { 151 #ifdef CONFIG_NET_RX_BUSY_POLL 152 WRITE_ONCE(sk->sk_napi_id, skb->napi_id); 153 #endif 154 sk_rx_queue_set(sk, skb); 155 } 156 157 static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id) 158 { 159 #ifdef CONFIG_NET_RX_BUSY_POLL 160 if (!READ_ONCE(sk->sk_napi_id)) 161 WRITE_ONCE(sk->sk_napi_id, napi_id); 162 #endif 163 } 164 165 /* variant used for unconnected sockets */ 166 static inline void sk_mark_napi_id_once(struct sock *sk, 167 const struct sk_buff *skb) 168 { 169 #ifdef CONFIG_NET_RX_BUSY_POLL 170 __sk_mark_napi_id_once(sk, skb->napi_id); 171 #endif 172 } 173 174 static inline void sk_mark_napi_id_once_xdp(struct sock *sk, 175 const struct xdp_buff *xdp) 176 { 177 #ifdef CONFIG_NET_RX_BUSY_POLL 178 __sk_mark_napi_id_once(sk, xdp->rxq->napi_id); 179 #endif 180 } 181 182 #endif /* _LINUX_NET_BUSY_POLL_H */ 183