xref: /linux/include/net/busy_poll.h (revision 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95)
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 
napi_id_valid(unsigned int napi_id)27 static inline bool napi_id_valid(unsigned int napi_id)
28 {
29 	return napi_id >= MIN_NAPI_ID;
30 }
31 
32 #define BUSY_POLL_BUDGET 8
33 
34 #ifdef CONFIG_NET_RX_BUSY_POLL
35 
36 struct napi_struct;
37 extern unsigned int sysctl_net_busy_read __read_mostly;
38 extern unsigned int sysctl_net_busy_poll __read_mostly;
39 
net_busy_loop_on(void)40 static inline bool net_busy_loop_on(void)
41 {
42 	return READ_ONCE(sysctl_net_busy_poll);
43 }
44 
sk_can_busy_loop(const struct sock * sk)45 static inline bool sk_can_busy_loop(const struct sock *sk)
46 {
47 	return READ_ONCE(sk->sk_ll_usec) && !signal_pending(current);
48 }
49 
50 bool sk_busy_loop_end(void *p, unsigned long start_time);
51 
52 void napi_busy_loop(unsigned int napi_id,
53 		    bool (*loop_end)(void *, unsigned long),
54 		    void *loop_end_arg, bool prefer_busy_poll, u16 budget);
55 
56 void napi_busy_loop_rcu(unsigned int napi_id,
57 			bool (*loop_end)(void *, unsigned long),
58 			void *loop_end_arg, bool prefer_busy_poll, u16 budget);
59 
60 void napi_suspend_irqs(unsigned int napi_id);
61 void napi_resume_irqs(unsigned int napi_id);
62 
63 #else /* CONFIG_NET_RX_BUSY_POLL */
net_busy_loop_on(void)64 static inline unsigned long net_busy_loop_on(void)
65 {
66 	return 0;
67 }
68 
sk_can_busy_loop(struct sock * sk)69 static inline bool sk_can_busy_loop(struct sock *sk)
70 {
71 	return false;
72 }
73 
74 #endif /* CONFIG_NET_RX_BUSY_POLL */
75 
busy_loop_current_time(void)76 static inline unsigned long busy_loop_current_time(void)
77 {
78 #ifdef CONFIG_NET_RX_BUSY_POLL
79 	return (unsigned long)(ktime_get_ns() >> 10);
80 #else
81 	return 0;
82 #endif
83 }
84 
85 /* in poll/select we use the global sysctl_net_ll_poll value */
busy_loop_timeout(unsigned long start_time)86 static inline bool busy_loop_timeout(unsigned long start_time)
87 {
88 #ifdef CONFIG_NET_RX_BUSY_POLL
89 	unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);
90 
91 	if (bp_usec) {
92 		unsigned long end_time = start_time + bp_usec;
93 		unsigned long now = busy_loop_current_time();
94 
95 		return time_after(now, end_time);
96 	}
97 #endif
98 	return true;
99 }
100 
sk_busy_loop_timeout(struct sock * sk,unsigned long start_time)101 static inline bool sk_busy_loop_timeout(struct sock *sk,
102 					unsigned long start_time)
103 {
104 #ifdef CONFIG_NET_RX_BUSY_POLL
105 	unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);
106 
107 	if (bp_usec) {
108 		unsigned long end_time = start_time + bp_usec;
109 		unsigned long now = busy_loop_current_time();
110 
111 		return time_after(now, end_time);
112 	}
113 #endif
114 	return true;
115 }
116 
sk_busy_loop(struct sock * sk,int nonblock)117 static inline void sk_busy_loop(struct sock *sk, int nonblock)
118 {
119 #ifdef CONFIG_NET_RX_BUSY_POLL
120 	unsigned int napi_id = READ_ONCE(sk->sk_napi_id);
121 
122 	if (napi_id_valid(napi_id))
123 		napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk,
124 			       READ_ONCE(sk->sk_prefer_busy_poll),
125 			       READ_ONCE(sk->sk_busy_poll_budget) ?: BUSY_POLL_BUDGET);
126 #endif
127 }
128 
129 /* used in the NIC receive handler to mark the skb */
__skb_mark_napi_id(struct sk_buff * skb,const struct gro_node * gro)130 static inline void __skb_mark_napi_id(struct sk_buff *skb,
131 				      const struct gro_node *gro)
132 {
133 #ifdef CONFIG_NET_RX_BUSY_POLL
134 	/* If the skb was already marked with a valid NAPI ID, avoid overwriting
135 	 * it.
136 	 */
137 	if (!napi_id_valid(skb->napi_id))
138 		skb->napi_id = gro->cached_napi_id;
139 #endif
140 }
141 
skb_mark_napi_id(struct sk_buff * skb,const struct napi_struct * napi)142 static inline void skb_mark_napi_id(struct sk_buff *skb,
143 				    const struct napi_struct *napi)
144 {
145 	__skb_mark_napi_id(skb, &napi->gro);
146 }
147 
148 /* 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)149 static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
150 {
151 #ifdef CONFIG_NET_RX_BUSY_POLL
152 	if (unlikely(READ_ONCE(sk->sk_napi_id) != skb->napi_id))
153 		WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
154 #endif
155 	sk_rx_queue_update(sk, skb);
156 }
157 
158 /* Variant of sk_mark_napi_id() for passive flow setup,
159  * as sk->sk_napi_id and sk->sk_rx_queue_mapping content
160  * needs to be set.
161  */
sk_mark_napi_id_set(struct sock * sk,const struct sk_buff * skb)162 static inline void sk_mark_napi_id_set(struct sock *sk,
163 				       const struct sk_buff *skb)
164 {
165 #ifdef CONFIG_NET_RX_BUSY_POLL
166 	WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
167 #endif
168 	sk_rx_queue_set(sk, skb);
169 }
170 
__sk_mark_napi_id_once(struct sock * sk,unsigned int napi_id)171 static inline void __sk_mark_napi_id_once(struct sock *sk, unsigned int napi_id)
172 {
173 #ifdef CONFIG_NET_RX_BUSY_POLL
174 	if (!READ_ONCE(sk->sk_napi_id))
175 		WRITE_ONCE(sk->sk_napi_id, napi_id);
176 #endif
177 }
178 
179 /* variant used for unconnected sockets */
sk_mark_napi_id_once(struct sock * sk,const struct sk_buff * skb)180 static inline void sk_mark_napi_id_once(struct sock *sk,
181 					const struct sk_buff *skb)
182 {
183 #ifdef CONFIG_NET_RX_BUSY_POLL
184 	__sk_mark_napi_id_once(sk, skb->napi_id);
185 #endif
186 }
187 
188 #endif /* _LINUX_NET_BUSY_POLL_H */
189