summaryrefslogtreecommitdiff
path: root/include/linux/rcutiny.h
blob: 4cc5eba41616c25283e4e168ca01cec38b9bb9e2 (plain)
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
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
/*
 * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 * Copyright IBM Corporation, 2008
 *
 * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
 *
 * For detailed explanation of Read-Copy Update mechanism see -
 *		Documentation/RCU
 */
#ifndef __LINUX_TINY_H
#define __LINUX_TINY_H

#include <linux/cache.h>

void rcu_sched_qs(int cpu);
void rcu_bh_qs(int cpu);

#ifdef CONFIG_TINY_RCU
#define __rcu_read_lock()	preempt_disable()
#define __rcu_read_unlock()	preempt_enable()
#else /* #ifdef CONFIG_TINY_RCU */
void __rcu_read_lock(void);
void __rcu_read_unlock(void);
#endif /* #else #ifdef CONFIG_TINY_RCU */
#define __rcu_read_lock_bh()	local_bh_disable()
#define __rcu_read_unlock_bh()	local_bh_enable()
extern void call_rcu_sched(struct rcu_head *head,
			   void (*func)(struct rcu_head *rcu));

#define rcu_init_sched()	do { } while (0)

extern void synchronize_sched(void);

#ifdef CONFIG_TINY_RCU

#define call_rcu		call_rcu_sched

static inline void synchronize_rcu(void)
{
	synchronize_sched();
}

static inline void synchronize_rcu_expedited(void)
{
	synchronize_sched();	/* Only one CPU, so pretty fast anyway!!! */
}

static inline void rcu_barrier(void)
{
	rcu_barrier_sched();  /* Only one CPU, so only one list of callbacks! */
}

#else /* #ifdef CONFIG_TINY_RCU */

void synchronize_rcu(void);
void rcu_barrier(void);
void synchronize_rcu_expedited(void);

#endif /* #else #ifdef CONFIG_TINY_RCU */

static inline void synchronize_rcu_bh(void)
{
	synchronize_sched();
}

static inline void synchronize_rcu_bh_expedited(void)
{
	synchronize_sched();
}

struct notifier_block;

#ifdef CONFIG_NO_HZ

extern void rcu_enter_nohz(void);
extern void rcu_exit_nohz(void);

#else /* #ifdef CONFIG_NO_HZ */

static inline void rcu_enter_nohz(void)
{
}

static inline void rcu_exit_nohz(void)
{
}

#endif /* #else #ifdef CONFIG_NO_HZ */

#ifdef CONFIG_TINY_RCU

static inline void rcu_preempt_note_context_switch(void)
{
}

static inline void exit_rcu(void)
{
}

static inline int rcu_needs_cpu(int cpu)
{
	return 0;
}

static inline int rcu_preempt_depth(void)
{
	return 0;
}

#else /* #ifdef CONFIG_TINY_RCU */

void rcu_preempt_note_context_switch(void);
extern void exit_rcu(void);
int rcu_preempt_needs_cpu(void);

static inline int rcu_needs_cpu(int cpu)
{
	return rcu_preempt_needs_cpu();
}

/*
 * Defined as macro as it is a very low level header
 * included from areas that don't even know about current
 * FIXME: combine with include/linux/rcutree.h into rcupdate.h.
 */
#define rcu_preempt_depth() (current->rcu_read_lock_nesting)

#endif /* #else #ifdef CONFIG_TINY_RCU */

static inline void rcu_note_context_switch(int cpu)
{
	rcu_sched_qs(cpu);
	rcu_preempt_note_context_switch();
}

extern void rcu_check_callbacks(int cpu, int user);

/*
 * Return the number of grace periods.
 */
static inline long rcu_batches_completed(void)
{
	return 0;
}

/*
 * Return the number of bottom-half grace periods.
 */
static inline long rcu_batches_completed_bh(void)
{
	return 0;
}

static inline void rcu_force_quiescent_state(void)
{
}

static inline void rcu_bh_force_quiescent_state(void)
{
}

static inline void rcu_sched_force_quiescent_state(void)
{
}

#ifdef CONFIG_DEBUG_LOCK_ALLOC

extern int rcu_scheduler_active __read_mostly;
extern void rcu_scheduler_starting(void);

#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */

static inline void rcu_scheduler_starting(void)
{
}

#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */

#endif /* __LINUX_RCUTINY_H */