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1/*
2 * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright IBM Corporation, 2008
19 *
20 * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
21 *
22 * For detailed explanation of Read-Copy Update mechanism see -
23 * Documentation/RCU
24 */
25#ifndef __LINUX_TINY_H
26#define __LINUX_TINY_H
27
28#include <linux/cache.h>
29
30#ifdef CONFIG_RCU_BOOST
31static inline void rcu_init(void)
32{
33}
34#else /* #ifdef CONFIG_RCU_BOOST */
35void rcu_init(void);
36#endif /* #else #ifdef CONFIG_RCU_BOOST */
37
38static inline void rcu_barrier_bh(void)
39{
40 wait_rcu_gp(call_rcu_bh);
41}
42
43static inline void rcu_barrier_sched(void)
44{
45 wait_rcu_gp(call_rcu_sched);
46}
47
48#ifdef CONFIG_TINY_RCU
49
50static inline void synchronize_rcu_expedited(void)
51{
52 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
53}
54
55static inline void rcu_barrier(void)
56{
57 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
58}
59
60#else /* #ifdef CONFIG_TINY_RCU */
61
62void synchronize_rcu_expedited(void);
63
64static inline void rcu_barrier(void)
65{
66 wait_rcu_gp(call_rcu);
67}
68
69#endif /* #else #ifdef CONFIG_TINY_RCU */
70
71static inline void synchronize_rcu_bh(void)
72{
73 synchronize_sched();
74}
75
76static inline void synchronize_rcu_bh_expedited(void)
77{
78 synchronize_sched();
79}
80
81static inline void synchronize_sched_expedited(void)
82{
83 synchronize_sched();
84}
85
86#ifdef CONFIG_TINY_RCU
87
88static inline void rcu_preempt_note_context_switch(void)
89{
90}
91
92static inline void exit_rcu(void)
93{
94}
95
96static inline int rcu_needs_cpu(int cpu)
97{
98 return 0;
99}
100
101#else /* #ifdef CONFIG_TINY_RCU */
102
103void rcu_preempt_note_context_switch(void);
104extern void exit_rcu(void);
105int rcu_preempt_needs_cpu(void);
106
107static inline int rcu_needs_cpu(int cpu)
108{
109 return rcu_preempt_needs_cpu();
110}
111
112#endif /* #else #ifdef CONFIG_TINY_RCU */
113
114static inline void rcu_note_context_switch(int cpu)
115{
116 rcu_sched_qs(cpu);
117 rcu_preempt_note_context_switch();
118}
119
120/*
121 * Take advantage of the fact that there is only one CPU, which
122 * allows us to ignore virtualization-based context switches.
123 */
124static inline void rcu_virt_note_context_switch(int cpu)
125{
126}
127
128/*
129 * Return the number of grace periods.
130 */
131static inline long rcu_batches_completed(void)
132{
133 return 0;
134}
135
136/*
137 * Return the number of bottom-half grace periods.
138 */
139static inline long rcu_batches_completed_bh(void)
140{
141 return 0;
142}
143
144static inline void rcu_force_quiescent_state(void)
145{
146}
147
148static inline void rcu_bh_force_quiescent_state(void)
149{
150}
151
152static inline void rcu_sched_force_quiescent_state(void)
153{
154}
155
156static inline void rcu_cpu_stall_reset(void)
157{
158}
159
160#ifdef CONFIG_DEBUG_LOCK_ALLOC
161extern int rcu_scheduler_active __read_mostly;
162extern void rcu_scheduler_starting(void);
163#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
164static inline void rcu_scheduler_starting(void)
165{
166}
167#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
168
169#endif /* __LINUX_RCUTINY_H */