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 #else /* CONFIG_NET_RX_BUSY_POLL */ 52 static inline unsigned long net_busy_loop_on(void) 53 { 54 return 0; 55 } 56 57 static inline bool sk_can_busy_loop(struct sock *sk) 58 { 59 return false; 60 } 61 62 #endif /* CONFIG_NET_RX_BUSY_POLL */ 63 64 static inline unsigned long busy_loop_current_time(void) 65 { 66 #ifdef CONFIG_NET_RX_BUSY_POLL 67 return (unsigned long)(local_clock() >> 10); 68 #else 69 return 0; 70 #endif 71 } 72 73 /* in poll/select we use the global sysctl_net_ll_poll value */ 74 static inline bool busy_loop_timeout(unsigned long start_time) 75 { 76 #ifdef CONFIG_NET_RX_BUSY_POLL 77 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll); 78 79 if (bp_usec) { 80 unsigned long end_time = start_time + bp_usec; 81 unsigned long now = busy_loop_current_time(); 82 83 return time_after(now, end_time); 84 } 85 #endif 86 return true; 87 } 88 89 static inline bool sk_busy_loop_timeout(struct sock *sk, 90 unsigned long start_time) 91 { 92 #ifdef CONFIG_NET_RX_BUSY_POLL 93 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec); 94 95 if (bp_usec) { 96 unsigned long end_time = start_time + bp_usec; 97 unsigned long now = busy_loop_current_time(); 98 99 return time_after(now, end_time); 100 } 101 #endif 102 return true; 103 } 104 105 static inline void sk_busy_loop(struct sock *sk, int nonblock) 106 { 107 #ifdef CONFIG_NET_RX_BUSY_POLL 108 unsigned int napi_id = READ_ONCE(sk->sk_napi_id); 109 110 if (napi_id >= MIN_NAPI_ID) 111 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk, 112 READ_ONCE(sk->sk_prefer_busy_poll), 113 READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET); 114 #endif 115 } 116 117 /* used in the NIC receive handler to mark the skb */ 118 static inline void skb_mark_napi_id(struct sk_buff *skb, 119 struct napi_struct *napi) 120 { 121 #ifdef CONFIG_NET_RX_BUSY_POLL 122 /* If the skb was already marked with a valid NAPI ID, avoid overwriting 123 * it. 124 */ 125 if (skb->napi_id < MIN_NAPI_ID) 126 skb->napi_id = napi->napi_id; 127 #endif 128 } 129 130 /* used in the protocol hanlder to propagate the napi_id to the socket */ 131 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb) 132 { 133 #ifdef CONFIG_NET_RX_BUSY_POLL 134 if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id)) 135 WRITE_ONCE(sk->sk_napi_id, skb->napi_id); 136 #endif 137 sk_rx_queue_update(sk, skb); 138 } 139 140 /* Variant of sk_mark_napi_id() for passive flow setup, 141 * as sk->sk_napi_id and sk->sk_rx_queue_mapping content 142 * needs to be set. 143 */ 144 static inline void sk_mark_napi_id_set(struct sock *sk, 145 const struct sk_buff *skb) 146 { 147 #ifdef CONFIG_NET_RX_BUSY_POLL 148 WRITE_ONCE(sk->sk_napi_id, skb->napi_id); 149 #endif 150 sk_rx_queue_set(sk, skb); 151 } 152 153 static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id) 154 { 155 #ifdef CONFIG_NET_RX_BUSY_POLL 156 if (!READ_ONCE(sk->sk_napi_id)) 157 WRITE_ONCE(sk->sk_napi_id, napi_id); 158 #endif 159 } 160 161 /* variant used for unconnected sockets */ 162 static inline void sk_mark_napi_id_once(struct sock *sk, 163 const struct sk_buff *skb) 164 { 165 #ifdef CONFIG_NET_RX_BUSY_POLL 166 __sk_mark_napi_id_once(sk, skb->napi_id); 167 #endif 168 } 169 170 static inline void sk_mark_napi_id_once_xdp(struct sock *sk, 171 const struct xdp_buff *xdp) 172 { 173 #ifdef CONFIG_NET_RX_BUSY_POLL 174 __sk_mark_napi_id_once(sk, xdp->rxq->napi_id); 175 #endif 176 } 177 178 #endif /* _LINUX_NET_BUSY_POLL_H */ 179