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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 <linux/sched/clock.h> | |
29 | #include <linux/sched/signal.h> | |
30 | #include <net/ip.h> | |
31 | ||
32 | /* 0 - Reserved to indicate value not set | |
33 | * 1..NR_CPUS - Reserved for sender_cpu | |
34 | * NR_CPUS+1..~0 - Region available for NAPI IDs | |
35 | */ | |
36 | #define MIN_NAPI_ID ((unsigned int)(NR_CPUS + 1)) | |
37 | ||
38 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
39 | ||
40 | struct napi_struct; | |
41 | extern unsigned int sysctl_net_busy_read __read_mostly; | |
42 | extern unsigned int sysctl_net_busy_poll __read_mostly; | |
43 | ||
44 | static inline bool net_busy_loop_on(void) | |
45 | { | |
46 | return sysctl_net_busy_poll; | |
47 | } | |
48 | ||
49 | static inline bool sk_can_busy_loop(const struct sock *sk) | |
50 | { | |
51 | return sk->sk_ll_usec && !signal_pending(current); | |
52 | } | |
53 | ||
54 | bool sk_busy_loop_end(void *p, unsigned long start_time); | |
55 | ||
56 | void napi_busy_loop(unsigned int napi_id, | |
57 | bool (*loop_end)(void *, unsigned long), | |
58 | void *loop_end_arg); | |
59 | ||
60 | #else /* CONFIG_NET_RX_BUSY_POLL */ | |
61 | static inline unsigned long net_busy_loop_on(void) | |
62 | { | |
63 | return 0; | |
64 | } | |
65 | ||
66 | static inline bool sk_can_busy_loop(struct sock *sk) | |
67 | { | |
68 | return false; | |
69 | } | |
70 | ||
71 | #endif /* CONFIG_NET_RX_BUSY_POLL */ | |
72 | ||
73 | static inline unsigned long busy_loop_current_time(void) | |
74 | { | |
75 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
76 | return (unsigned long)(local_clock() >> 10); | |
77 | #else | |
78 | return 0; | |
79 | #endif | |
80 | } | |
81 | ||
82 | /* in poll/select we use the global sysctl_net_ll_poll value */ | |
83 | static inline bool busy_loop_timeout(unsigned long start_time) | |
84 | { | |
85 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
86 | unsigned long bp_usec = READ_ONCE(sysctl_net_busy_poll); | |
87 | ||
88 | if (bp_usec) { | |
89 | unsigned long end_time = start_time + bp_usec; | |
90 | unsigned long now = busy_loop_current_time(); | |
91 | ||
92 | return time_after(now, end_time); | |
93 | } | |
94 | #endif | |
95 | return true; | |
96 | } | |
97 | ||
98 | static inline bool sk_busy_loop_timeout(struct sock *sk, | |
99 | unsigned long start_time) | |
100 | { | |
101 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
102 | unsigned long bp_usec = READ_ONCE(sk->sk_ll_usec); | |
103 | ||
104 | if (bp_usec) { | |
105 | unsigned long end_time = start_time + bp_usec; | |
106 | unsigned long now = busy_loop_current_time(); | |
107 | ||
108 | return time_after(now, end_time); | |
109 | } | |
110 | #endif | |
111 | return true; | |
112 | } | |
113 | ||
114 | static inline void sk_busy_loop(struct sock *sk, int nonblock) | |
115 | { | |
116 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
117 | unsigned int napi_id = READ_ONCE(sk->sk_napi_id); | |
118 | ||
119 | if (napi_id >= MIN_NAPI_ID) | |
120 | napi_busy_loop(napi_id, nonblock ? NULL : sk_busy_loop_end, sk); | |
121 | #endif | |
122 | } | |
123 | ||
124 | /* used in the NIC receive handler to mark the skb */ | |
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 | skb->napi_id = napi->napi_id; | |
130 | #endif | |
131 | } | |
132 | ||
133 | /* used in the protocol hanlder to propagate the napi_id to the socket */ | |
134 | static inline void sk_mark_napi_id(struct sock *sk, const struct sk_buff *skb) | |
135 | { | |
136 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
137 | sk->sk_napi_id = skb->napi_id; | |
138 | #endif | |
139 | sk_rx_queue_set(sk, skb); | |
140 | } | |
141 | ||
142 | /* variant used for unconnected sockets */ | |
143 | static inline void sk_mark_napi_id_once(struct sock *sk, | |
144 | const struct sk_buff *skb) | |
145 | { | |
146 | #ifdef CONFIG_NET_RX_BUSY_POLL | |
147 | if (!sk->sk_napi_id) | |
148 | sk->sk_napi_id = skb->napi_id; | |
149 | #endif | |
150 | } | |
151 | ||
152 | #endif /* _LINUX_NET_BUSY_POLL_H */ |