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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 <net/ip.h>
29
30#ifdef CONFIG_NET_RX_BUSY_POLL
31
32struct napi_struct;
33extern unsigned int sysctl_net_busy_read __read_mostly;
34extern unsigned int sysctl_net_busy_poll __read_mostly;
35
36/* return values from ndo_ll_poll */
37#define LL_FLUSH_FAILED -1
38#define LL_FLUSH_BUSY -2
39
40static inline bool net_busy_loop_on(void)
41{
42 return sysctl_net_busy_poll;
43}
44
45static inline u64 busy_loop_us_clock(void)
46{
47 return local_clock() >> 10;
48}
49
50static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
51{
52 return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
53}
54
55/* in poll/select we use the global sysctl_net_ll_poll value */
56static inline unsigned long busy_loop_end_time(void)
57{
58 return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
59}
60
61static inline bool sk_can_busy_loop(struct sock *sk)
62{
63 return sk->sk_ll_usec && sk->sk_napi_id &&
64 !need_resched() && !signal_pending(current);
65}
66
67
68static inline bool busy_loop_timeout(unsigned long end_time)
69{
70 unsigned long now = busy_loop_us_clock();
71
72 return time_after(now, end_time);
73}
74
75bool sk_busy_loop(struct sock *sk, int nonblock);
76
77/* used in the NIC receive handler to mark the skb */
78static inline void skb_mark_napi_id(struct sk_buff *skb,
79 struct napi_struct *napi)
80{
81 skb->napi_id = napi->napi_id;
82}
83
84/* used in the protocol hanlder to propagate the napi_id to the socket */
85static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
86{
87 sk->sk_napi_id = skb->napi_id;
88}
89
90#else /* CONFIG_NET_RX_BUSY_POLL */
91static inline unsigned long net_busy_loop_on(void)
92{
93 return 0;
94}
95
96static inline unsigned long busy_loop_end_time(void)
97{
98 return 0;
99}
100
101static inline bool sk_can_busy_loop(struct sock *sk)
102{
103 return false;
104}
105
106static inline void skb_mark_napi_id(struct sk_buff *skb,
107 struct napi_struct *napi)
108{
109}
110
111static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
112{
113}
114
115static inline bool busy_loop_timeout(unsigned long end_time)
116{
117 return true;
118}
119
120static inline bool sk_busy_loop(struct sock *sk, int nonblock)
121{
122 return false;
123}
124
125#endif /* CONFIG_NET_RX_BUSY_POLL */
126#endif /* _LINUX_NET_BUSY_POLL_H */
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 <net/ip.h>
29
30#ifdef CONFIG_NET_RX_BUSY_POLL
31
32struct napi_struct;
33extern unsigned int sysctl_net_busy_read __read_mostly;
34extern unsigned int sysctl_net_busy_poll __read_mostly;
35
36/* return values from ndo_ll_poll */
37#define LL_FLUSH_FAILED -1
38#define LL_FLUSH_BUSY -2
39
40static inline bool net_busy_loop_on(void)
41{
42 return sysctl_net_busy_poll;
43}
44
45static inline u64 busy_loop_us_clock(void)
46{
47 return local_clock() >> 10;
48}
49
50static inline unsigned long sk_busy_loop_end_time(struct sock *sk)
51{
52 return busy_loop_us_clock() + ACCESS_ONCE(sk->sk_ll_usec);
53}
54
55/* in poll/select we use the global sysctl_net_ll_poll value */
56static inline unsigned long busy_loop_end_time(void)
57{
58 return busy_loop_us_clock() + ACCESS_ONCE(sysctl_net_busy_poll);
59}
60
61static inline bool sk_can_busy_loop(struct sock *sk)
62{
63 return sk->sk_ll_usec && sk->sk_napi_id &&
64 !need_resched() && !signal_pending(current);
65}
66
67
68static inline bool busy_loop_timeout(unsigned long end_time)
69{
70 unsigned long now = busy_loop_us_clock();
71
72 return time_after(now, end_time);
73}
74
75/* when used in sock_poll() nonblock is known at compile time to be true
76 * so the loop and end_time will be optimized out
77 */
78static inline bool sk_busy_loop(struct sock *sk, int nonblock)
79{
80 unsigned long end_time = !nonblock ? sk_busy_loop_end_time(sk) : 0;
81 const struct net_device_ops *ops;
82 struct napi_struct *napi;
83 int rc = false;
84
85 /*
86 * rcu read lock for napi hash
87 * bh so we don't race with net_rx_action
88 */
89 rcu_read_lock_bh();
90
91 napi = napi_by_id(sk->sk_napi_id);
92 if (!napi)
93 goto out;
94
95 ops = napi->dev->netdev_ops;
96 if (!ops->ndo_busy_poll)
97 goto out;
98
99 do {
100 rc = ops->ndo_busy_poll(napi);
101
102 if (rc == LL_FLUSH_FAILED)
103 break; /* permanent failure */
104
105 if (rc > 0)
106 /* local bh are disabled so it is ok to use _BH */
107 NET_ADD_STATS_BH(sock_net(sk),
108 LINUX_MIB_BUSYPOLLRXPACKETS, rc);
109 cpu_relax();
110
111 } while (!nonblock && skb_queue_empty(&sk->sk_receive_queue) &&
112 !need_resched() && !busy_loop_timeout(end_time));
113
114 rc = !skb_queue_empty(&sk->sk_receive_queue);
115out:
116 rcu_read_unlock_bh();
117 return rc;
118}
119
120/* used in the NIC receive handler to mark the skb */
121static inline void skb_mark_napi_id(struct sk_buff *skb,
122 struct napi_struct *napi)
123{
124 skb->napi_id = napi->napi_id;
125}
126
127/* used in the protocol hanlder to propagate the napi_id to the socket */
128static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
129{
130 sk->sk_napi_id = skb->napi_id;
131}
132
133#else /* CONFIG_NET_RX_BUSY_POLL */
134static inline unsigned long net_busy_loop_on(void)
135{
136 return 0;
137}
138
139static inline unsigned long busy_loop_end_time(void)
140{
141 return 0;
142}
143
144static inline bool sk_can_busy_loop(struct sock *sk)
145{
146 return false;
147}
148
149static inline void skb_mark_napi_id(struct sk_buff *skb,
150 struct napi_struct *napi)
151{
152}
153
154static inline void sk_mark_napi_id(struct sock *sk, struct sk_buff *skb)
155{
156}
157
158static inline bool busy_loop_timeout(unsigned long end_time)
159{
160 return true;
161}
162
163static inline bool sk_busy_loop(struct sock *sk, int nonblock)
164{
165 return false;
166}
167
168#endif /* CONFIG_NET_RX_BUSY_POLL */
169#endif /* _LINUX_NET_BUSY_POLL_H */