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
net_busy_loop_on(void)35 static inline bool net_busy_loop_on(void)
36 {
37 return READ_ONCE(sysctl_net_busy_poll);
38 }
39
sk_can_busy_loop(const struct sock * sk)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 */
net_busy_loop_on(void)59 static inline unsigned long net_busy_loop_on(void)
60 {
61 return 0;
62 }
63
sk_can_busy_loop(struct sock * sk)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
busy_loop_current_time(void)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 */
busy_loop_timeout(unsigned long start_time)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
sk_busy_loop_timeout(struct sock * sk,unsigned long start_time)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
sk_busy_loop(struct sock * sk,int nonblock)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 */
skb_mark_napi_id(struct sk_buff * skb,struct napi_struct * napi)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 */
sk_mark_napi_id(struct sock * sk,const struct sk_buff * skb)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 */
sk_mark_napi_id_set(struct sock * sk,const struct sk_buff * skb)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
__sk_mark_napi_id_once(struct sock * sk,unsigned int napi_id)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 */
sk_mark_napi_id_once(struct sock * sk,const struct sk_buff * skb)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 #endif /* _LINUX_NET_BUSY_POLL_H */
178