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 <net/ip.h>
  29
  30 #ifdef CONFIG_NET_RX_BUSY_POLL
  31
  32 struct napi_struct;
  33 extern unsigned int sysctl_net_busy_read __read_mostly;
  34 extern unsigned int sysctl_net_busy_poll __read_mostly;
  35
  36 /* return values from ndo_ll_poll */
  37 #define LL_FLUSH_FAILED         -1
  38 #define LL_FLUSH_BUSY           -2
  39
  40 static inline bool net_busy_loop_on(void)
  41 {
  42         return sysctl_net_busy_poll;
  43 }
  44
  45 static inline u64 busy_loop_us_clock(void)
  46 {
  47         return local_clock() >> 10;
  48 }
  49
  50 static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
  51 {
  52         return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
  53 }
  54
  55 /* in poll/select we use the global sysctl_net_ll_poll value */
  56 static inline unsigned long busy_loop_end_time(void)
  57 {
  58         return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
  59 }
  60
  61 static inline bool sk_can_busy_loop(const struct sock *sk)
  62 {
  63         return sk->sk_ll_usec && sk->sk_napi_id && !signal_pending(current);
  64 }
  65
  66
  67 static inline bool busy_loop_timeout(unsigned long end_time)
  68 {
  69         unsigned long now = busy_loop_us_clock();
  70
  71         return time_after(now, end_time);
  72 }
  73
  74 bool sk_busy_loop(struct sock *sk, int nonblock);
  75
  76 /* used in the NIC receive handler to mark the skb */
  77 static inline void skb_mark_napi_id(struct sk_buff *skb,
  78                                     struct napi_struct *napi)
  79 {
  80         skb->napi_id = napi->napi_id;
  81 }
  82
  83
  84 #else /* CONFIG_NET_RX_BUSY_POLL */
  85 static inline unsigned long net_busy_loop_on(void)
  86 {
  87         return 0;
  88 }
  89
  90 static inline unsigned long busy_loop_end_time(void)
  91 {
  92         return 0;
  93 }
  94
  95 static inline bool sk_can_busy_loop(struct sock *sk)
  96 {
  97         return false;
  98 }
  99
 100 static inline void skb_mark_napi_id(struct sk_buff *skb,
 101                                     struct napi_struct *napi)
 102 {
 103 }
 104
 105 static inline bool busy_loop_timeout(unsigned long end_time)
 106 {
 107         return true;
 108 }
 109
 110 static inline bool sk_busy_loop(struct sock *sk, int nonblock)
 111 {
 112         return false;
 113 }
 114
 115 #endif /* CONFIG_NET_RX_BUSY_POLL */
 116
 117 /* used in the protocol hanlder to propagate the napi_id to the socket */
 118 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
 119 {
 120 #ifdef CONFIG_NET_RX_BUSY_POLL
 121         sk->sk_napi_id = skb->napi_id;
 122 #endif
 123 }
 124
 125 /* variant used for unconnected sockets */
 126 static inline void sk_mark_napi_id_once(struct sock *sk,
 127                                         const struct sk_buff *skb)
 128 {
 129 #ifdef CONFIG_NET_RX_BUSY_POLL
 130         if (!sk->sk_napi_id)
 131                 sk->sk_napi_id = skb->napi_id;
 132 #endif
 133 }
 134
 135 #endif /* _LINUX_NET_BUSY_POLL_H */