include/net/busy_poll.h

   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 #ifdef CONFIG_NET_RX_BUSY_POLL
  33
  34 struct napi_struct;
  35 extern unsigned int sysctl_net_busy_read __read_mostly;
  36 extern unsigned int sysctl_net_busy_poll __read_mostly;
  37
  38 static inline bool net_busy_loop_on(void)
  39 {
  40         return sysctl_net_busy_poll;
  41 }
  42
  43 static inline u64 busy_loop_us_clock(void)
  44 {
  45         return local_clock() >> 10;
  46 }
  47
  48 static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
  49 {
  50         return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
  51 }
  52
  53 /* in poll/select we use the global sysctl_net_ll_poll value */
  54 static inline unsigned long busy_loop_end_time(void)
  55 {
  56         return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
  57 }
  58
  59 static inline bool sk_can_busy_loop(const struct sock *sk)
  60 {
  61         return sk->sk_ll_usec && sk->sk_napi_id && !signal_pending(current);
  62 }
  63
  64
  65 static inline bool busy_loop_timeout(unsigned long end_time)
  66 {
  67         unsigned long now = busy_loop_us_clock();
  68
  69         return time_after(now, end_time);
  70 }
  71
  72 bool sk_busy_loop(struct sock *sk, int nonblock);
  73
  74 /* used in the NIC receive handler to mark the skb */
  75 static inline void skb_mark_napi_id(struct sk_buff *skb,
  76                                     struct napi_struct *napi)
  77 {
  78         skb->napi_id = napi->napi_id;
  79 }
  80
  81
  82 #else /* CONFIG_NET_RX_BUSY_POLL */
  83 static inline unsigned long net_busy_loop_on(void)
  84 {
  85         return 0;
  86 }
  87
  88 static inline unsigned long busy_loop_end_time(void)
  89 {
  90         return 0;
  91 }
  92
  93 static inline bool sk_can_busy_loop(struct sock *sk)
  94 {
  95         return false;
  96 }
  97
  98 static inline void skb_mark_napi_id(struct sk_buff *skb,
  99                                     struct napi_struct *napi)
 100 {
 101 }
 102
 103 static inline bool busy_loop_timeout(unsigned long end_time)
 104 {
 105         return true;
 106 }
 107
 108 static inline bool sk_busy_loop(struct sock *sk, int nonblock)
 109 {
 110         return false;
 111 }
 112
 113 #endif /* CONFIG_NET_RX_BUSY_POLL */
 114
 115 /* used in the protocol hanlder to propagate the napi_id to the socket */
 116 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
 117 {
 118 #ifdef CONFIG_NET_RX_BUSY_POLL
 119         sk->sk_napi_id = skb->napi_id;
 120 #endif
 121 }
 122
 123 /* variant used for unconnected sockets */
 124 static inline void sk_mark_napi_id_once(struct sock *sk,
 125                                         const struct sk_buff *skb)
 126 {
 127 #ifdef CONFIG_NET_RX_BUSY_POLL
 128         if (!sk->sk_napi_id)
 129                 sk->sk_napi_id = skb->napi_id;
 130 #endif
 131 }
 132
 133 #endif /* _LINUX_NET_BUSY_POLL_H */