include/net/busy_poll.h

   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 void napi_suspend_irqs(unsigned int napi_id);
  56 void napi_resume_irqs(unsigned int napi_id);
  57
  58 #else /* CONFIG_NET_RX_BUSY_POLL */
  59 static inline unsigned long net_busy_loop_on(void)
  60 {
  61         return 0;
  62 }
  63
  64 static inline bool sk_can_busy_loop(struct sock *sk)
  65 {
  66         return false;
  67 }
  68
  69 #endif /* CONFIG_NET_RX_BUSY_POLL */
  70
  71 static inline unsigned long busy_loop_current_time(void)
  72 {
  73 #ifdef CONFIG_NET_RX_BUSY_POLL
  74         return (unsigned long)(ktime_get_ns() >> 10);
  75 #else
  76         return 0;
  77 #endif
  78 }
  79
  80 /* in poll/select we use the global sysctl_net_ll_poll value */
  81 static inline bool busy_loop_timeout(unsigned long start_time)
  82 {
  83 #ifdef CONFIG_NET_RX_BUSY_POLL
  84         unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
  85
  86         if (bp_usec) {
  87                 unsigned long end_time = start_time + bp_usec;
  88                 unsigned long now = busy_loop_current_time();
  89
  90                 return time_after(now, end_time);
  91         }
  92 #endif
  93         return true;
  94 }
  95
  96 static inline bool sk_busy_loop_timeout(struct sock *sk,
  97                                         unsigned long start_time)
  98 {
  99 #ifdef CONFIG_NET_RX_BUSY_POLL
 100         unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
 101
 102         if (bp_usec) {
 103                 unsigned long end_time = start_time + bp_usec;
 104                 unsigned long now = busy_loop_current_time();
 105
 106                 return time_after(now, end_time);
 107         }
 108 #endif
 109         return true;
 110 }
 111
 112 static inline void sk_busy_loop(struct sock *sk, int nonblock)
 113 {
 114 #ifdef CONFIG_NET_RX_BUSY_POLL
 115         unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
 116
 117         if (napi_id >= MIN_NAPI_ID)
 118                 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
 119                                READ_ONCE(sk->sk_prefer_busy_poll),
 120                                READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
 121 #endif
 122 }
 123
 124 /* used in the NIC receive handler to mark the skb */
 125 static inline void skb_mark_napi_id(struct sk_buff *skb,
 126                                     struct napi_struct *napi)
 127 {
 128 #ifdef CONFIG_NET_RX_BUSY_POLL
 129         /* If the skb was already marked with a valid NAPI ID, avoid overwriting
 130          * it.
 131          */
 132         if (skb->napi_id < MIN_NAPI_ID)
 133                 skb->napi_id = napi->napi_id;
 134 #endif
 135 }
 136
 137 /* used in the protocol handler to propagate the napi_id to the socket */
 138 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
 139 {
 140 #ifdef CONFIG_NET_RX_BUSY_POLL
 141         if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
 142                 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
 143 #endif
 144         sk_rx_queue_update(sk, skb);
 145 }
 146
 147 /* Variant of sk_mark_napi_id() for passive flow setup,
 148  * as sk->sk_napi_id and sk->sk_rx_queue_mapping content
 149  * needs to be set.
 150  */
 151 static inline void sk_mark_napi_id_set(struct sock *sk,
 152                                        const struct sk_buff *skb)
 153 {
 154 #ifdef CONFIG_NET_RX_BUSY_POLL
 155         WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
 156 #endif
 157         sk_rx_queue_set(sk, skb);
 158 }
 159
 160 static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
 161 {
 162 #ifdef CONFIG_NET_RX_BUSY_POLL
 163         if (!READ_ONCE(sk->sk_napi_id))
 164                 WRITE_ONCE(sk->sk_napi_id, napi_id);
 165 #endif
 166 }
 167
 168 /* variant used for unconnected sockets */
 169 static inline void sk_mark_napi_id_once(struct sock *sk,
 170                                         const struct sk_buff *skb)
 171 {
 172 #ifdef CONFIG_NET_RX_BUSY_POLL
 173         __sk_mark_napi_id_once(sk, skb->napi_id);
 174 #endif
 175 }
 176
 177 static inline void sk_mark_napi_id_once_xdp(struct sock *sk,
 178                                             const struct xdp_buff *xdp)
 179 {
 180 #ifdef CONFIG_NET_RX_BUSY_POLL
 181         __sk_mark_napi_id_once(sk, xdp->rxq->napi_id);
 182 #endif
 183 }
 184
 185 #endif /* _LINUX_NET_BUSY_POLL_H */