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