aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/include/net/busy_poll.h
blob: 86e028388badc46977bf6c05bd8f718d852c14a8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * net busy poll support
 * Copyright(c) 2013 Intel Corporation.
 *
 * Author: Eliezer Tamir
 *
 * Contact Information:
 * e1000-devel Mailing List <e1000-devel@lists.sourceforge.net>
 */

#ifndef _LINUX_NET_BUSY_POLL_H
#define _LINUX_NET_BUSY_POLL_H

#include <linux/netdevice.h>
#include <linux/sched/clock.h>
#include <linux/sched/signal.h>
#include <net/ip.h>

/*		0 - Reserved to indicate value not set
 *     1..NR_CPUS - Reserved for sender_cpu
 *  NR_CPUS+1..~0 - Region available for NAPI IDs
 */
#define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1))

#ifdef CONFIG_NET_RX_BUSY_POLL

struct napi_struct;
extern unsigned int sysctl_net_busy_read __read_mostly;
extern unsigned int sysctl_net_busy_poll __read_mostly;

static inline bool net_busy_loop_on(void)
{
	return sysctl_net_busy_poll;
}

static inline bool sk_can_busy_loop(const struct sock *sk)
{
	return sk->sk_ll_usec && !signal_pending(current);
}

bool sk_busy_loop_end(void *p, unsigned long start_time);

void napi_busy_loop(unsigned int napi_id,
		    bool (*loop_end)(void *, unsigned long),
		    void *loop_end_arg);

#else /* CONFIG_NET_RX_BUSY_POLL */
static inline unsigned long net_busy_loop_on(void)
{
	return 0;
}

static inline bool sk_can_busy_loop(struct sock *sk)
{
	return false;
}

#endif /* CONFIG_NET_RX_BUSY_POLL */

static inline unsigned long busy_loop_current_time(void)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	return (unsigned long)(local_clock() >> 10);
#else
	return 0;
#endif
}

/* in poll/select we use the global sysctl_net_ll_poll value */
static inline bool busy_loop_timeout(unsigned long start_time)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll);

	if (bp_usec) {
		unsigned long end_time = start_time + bp_usec;
		unsigned long now = busy_loop_current_time();

		return time_after(now, end_time);
	}
#endif
	return true;
}

static inline bool sk_busy_loop_timeout(struct sock *sk,
					unsigned long start_time)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec);

	if (bp_usec) {
		unsigned long end_time = start_time + bp_usec;
		unsigned long now = busy_loop_current_time();

		return time_after(now, end_time);
	}
#endif
	return true;
}

static inline void sk_busy_loop(struct sock *sk, int nonblock)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	unsigned int napi_id = READ_ONCE(sk->sk_napi_id);

	if (napi_id >= MIN_NAPI_ID)
		napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk);
#endif
}

/* used in the NIC receive handler to mark the skb */
static inline void skb_mark_napi_id(struct sk_buff *skb,
				    struct napi_struct *napi)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	skb->napi_id = napi->napi_id;
#endif
}

/* used in the protocol hanlder to propagate the napi_id to the socket */
static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
#endif
	sk_rx_queue_set(sk, skb);
}

/* variant used for unconnected sockets */
static inline void sk_mark_napi_id_once(struct sock *sk,
					const struct sk_buff *skb)
{
#ifdef CONFIG_NET_RX_BUSY_POLL
	if (!READ_ONCE(sk->sk_napi_id))
		WRITE_ONCE(sk->sk_napi_id, skb->napi_id);
#endif
}

#endif /* _LINUX_NET_BUSY_POLL_H */