xref: /openbmc/linux/include/net/busy_poll.h (revision 8571e645)
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(struct sock *sk)
62 {
63 	return sk->sk_ll_usec && sk->sk_napi_id &&
64 	       !need_resched() && !signal_pending(current);
65 }
66 
67 
68 static inline bool busy_loop_timeout(unsigned long end_time)
69 {
70 	unsigned long now = busy_loop_us_clock();
71 
72 	return time_after(now, end_time);
73 }
74 
75 bool sk_busy_loop(struct sock *sk, int nonblock);
76 
77 /* used in the NIC receive handler to mark the skb */
78 static inline void skb_mark_napi_id(struct sk_buff *skb,
79 				    struct napi_struct *napi)
80 {
81 	skb->napi_id = napi->napi_id;
82 }
83 
84 /* used in the protocol hanlder to propagate the napi_id to the socket */
85 static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
86 {
87 	sk->sk_napi_id = skb->napi_id;
88 }
89 
90 #else /* CONFIG_NET_RX_BUSY_POLL */
91 static inline unsigned long net_busy_loop_on(void)
92 {
93 	return 0;
94 }
95 
96 static inline unsigned long busy_loop_end_time(void)
97 {
98 	return 0;
99 }
100 
101 static inline bool sk_can_busy_loop(struct sock *sk)
102 {
103 	return false;
104 }
105 
106 static inline void skb_mark_napi_id(struct sk_buff *skb,
107 				    struct napi_struct *napi)
108 {
109 }
110 
111 static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
112 {
113 }
114 
115 static inline bool busy_loop_timeout(unsigned long end_time)
116 {
117 	return true;
118 }
119 
120 static inline bool sk_busy_loop(struct sock *sk, int nonblock)
121 {
122 	return false;
123 }
124 
125 #endif /* CONFIG_NET_RX_BUSY_POLL */
126 #endif /* _LINUX_NET_BUSY_POLL_H */
127