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 #else /* CONFIG_NET_RX_BUSY_POLL */
net_busy_loop_on(void)52 static inline unsigned long net_busy_loop_on(void)
53 {
54 return 0;
55 }
56
sk_can_busy_loop(struct sock * sk)57 static inline bool sk_can_busy_loop(struct sock *sk)
58 {
59 return false;
60 }
61
62 #endif /* CONFIG_NET_RX_BUSY_POLL */
63
busy_loop_current_time(void)64 static inline unsigned long busy_loop_current_time(void)
65 {
66 #ifdef CONFIG_NET_RX_BUSY_POLL
67 return (unsigned long)(local_clock() >> 10);
68 #else
69 return 0;
70 #endif
71 }
72
73 /* in poll/select we use the global sysctl_net_ll_poll value */
busy_loop_timeout(unsigned long start_time)74 static inline bool busy_loop_timeout(unsigned long start_time)
75 {
76 #ifdef CONFIG_NET_RX_BUSY_POLL
77 unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
78
79 if (bp_usec) {
80 unsigned long end_time = start_time + bp_usec;
81 unsigned long now = busy_loop_current_time();
82
83 return time_after(now, end_time);
84 }
85 #endif
86 return true;
87 }
88
sk_busy_loop_timeout(struct sock * sk,unsigned long start_time)89 static inline bool sk_busy_loop_timeout(struct sock *sk,
90 unsigned long start_time)
91 {
92 #ifdef CONFIG_NET_RX_BUSY_POLL
93 unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
94
95 if (bp_usec) {
96 unsigned long end_time = start_time + bp_usec;
97 unsigned long now = busy_loop_current_time();
98
99 return time_after(now, end_time);
100 }
101 #endif
102 return true;
103 }
104
sk_busy_loop(struct sock * sk,int nonblock)105 static inline void sk_busy_loop(struct sock *sk, int nonblock)
106 {
107 #ifdef CONFIG_NET_RX_BUSY_POLL
108 unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
109
110 if (napi_id >= MIN_NAPI_ID)
111 napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
112 READ_ONCE(sk->sk_prefer_busy_poll),
113 READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
114 #endif
115 }
116
117 /* used in the NIC receive handler to mark the skb */
skb_mark_napi_id(struct sk_buff * skb,struct napi_struct * napi)118 static inline void skb_mark_napi_id(struct sk_buff *skb,
119 struct napi_struct *napi)
120 {
121 #ifdef CONFIG_NET_RX_BUSY_POLL
122 /* If the skb was already marked with a valid NAPI ID, avoid overwriting
123 * it.
124 */
125 if (skb->napi_id < MIN_NAPI_ID)
126 skb->napi_id = napi->napi_id;
127 #endif
128 }
129
130 /* used in the protocol hanlder to propagate the napi_id to the socket */
sk_mark_napi_id(struct sock * sk,const struct sk_buff * skb)131 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
132 {
133 #ifdef CONFIG_NET_RX_BUSY_POLL
134 if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
135 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
136 #endif
137 sk_rx_queue_update(sk, skb);
138 }
139
140 /* Variant of sk_mark_napi_id() for passive flow setup,
141 * as sk->sk_napi_id and sk->sk_rx_queue_mapping content
142 * needs to be set.
143 */
sk_mark_napi_id_set(struct sock * sk,const struct sk_buff * skb)144 static inline void sk_mark_napi_id_set(struct sock *sk,
145 const struct sk_buff *skb)
146 {
147 #ifdef CONFIG_NET_RX_BUSY_POLL
148 WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
149 #endif
150 sk_rx_queue_set(sk, skb);
151 }
152
__sk_mark_napi_id_once(struct sock * sk,unsigned int napi_id)153 static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
154 {
155 #ifdef CONFIG_NET_RX_BUSY_POLL
156 if (!READ_ONCE(sk->sk_napi_id))
157 WRITE_ONCE(sk->sk_napi_id, napi_id);
158 #endif
159 }
160
161 /* variant used for unconnected sockets */
sk_mark_napi_id_once(struct sock * sk,const struct sk_buff * skb)162 static inline void sk_mark_napi_id_once(struct sock *sk,
163 const struct sk_buff *skb)
164 {
165 #ifdef CONFIG_NET_RX_BUSY_POLL
166 __sk_mark_napi_id_once(sk, skb->napi_id);
167 #endif
168 }
169
sk_mark_napi_id_once_xdp(struct sock * sk,const struct xdp_buff * xdp)170 static inline void sk_mark_napi_id_once_xdp(struct sock *sk,
171 const struct xdp_buff *xdp)
172 {
173 #ifdef CONFIG_NET_RX_BUSY_POLL
174 __sk_mark_napi_id_once(sk, xdp->rxq->napi_id);
175 #endif
176 }
177
178 #endif /* _LINUX_NET_BUSY_POLL_H */
179