summaryrefslogtreecommitdiff
path: root/include/linux/rcutiny.h
blob: 4e56a9c69a356ca73fcd06cf775f337276f77f2e (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
/*
 * 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>

static inline void rcu_init(void)
{
}

static inline void rcu_barrier_bh(void)
{
	wait_rcu_gp(call_rcu_bh);
}

static inline void rcu_barrier_sched(void)
{
	wait_rcu_gp(call_rcu_sched);
}

#ifdef CONFIG_TINY_RCU

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_expedited(void);

static inline void rcu_barrier(void)
{
	wait_rcu_gp(call_rcu);
}

#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();
}

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

static inline void kfree_call_rcu(struct rcu_head *head,
				  void (*func)(struct rcu_head *rcu))
{
	call_rcu(head, func);
}

#ifdef CONFIG_TINY_RCU

static inline void rcu_preempt_note_context_switch(void)
{
}

static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
	*delta_jiffies = ULONG_MAX;
	return 0;
}

#else /* #ifdef CONFIG_TINY_RCU */

void rcu_preempt_note_context_switch(void);
int rcu_preempt_needs_cpu(void);

static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
	*delta_jiffies = ULONG_MAX;
	return rcu_preempt_needs_cpu();
}

#endif /* #else #ifdef CONFIG_TINY_RCU */

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

/*
 * Take advantage of the fact that there is only one CPU, which
 * allows us to ignore virtualization-based context switches.
 */
static inline void rcu_virt_note_context_switch(int cpu)
{
}

/*
 * 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)
{
}

static inline void rcu_cpu_stall_reset(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 */