Linux kernel mirror (for testing)
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1/*
2 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
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: Dipankar Sarma <dipankar@in.ibm.com>
21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
22 *
23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
25 *
26 * For detailed explanation of Read-Copy Update mechanism see -
27 * Documentation/RCU
28 */
29
30#ifndef __LINUX_RCUTREE_H
31#define __LINUX_RCUTREE_H
32
33struct notifier_block;
34
35extern void rcu_sched_qs(int cpu);
36extern void rcu_bh_qs(int cpu);
37extern int rcu_cpu_notify(struct notifier_block *self,
38 unsigned long action, void *hcpu);
39extern int rcu_needs_cpu(int cpu);
40extern int rcu_expedited_torture_stats(char *page);
41
42#ifdef CONFIG_TREE_PREEMPT_RCU
43
44extern void __rcu_read_lock(void);
45extern void __rcu_read_unlock(void);
46extern void exit_rcu(void);
47
48#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
49
50static inline void __rcu_read_lock(void)
51{
52 preempt_disable();
53}
54
55static inline void __rcu_read_unlock(void)
56{
57 preempt_enable();
58}
59
60#define __synchronize_sched() synchronize_rcu()
61
62static inline void exit_rcu(void)
63{
64}
65
66#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
67
68static inline void __rcu_read_lock_bh(void)
69{
70 local_bh_disable();
71}
72static inline void __rcu_read_unlock_bh(void)
73{
74 local_bh_enable();
75}
76
77extern void call_rcu_sched(struct rcu_head *head,
78 void (*func)(struct rcu_head *rcu));
79extern void synchronize_rcu_expedited(void);
80
81static inline void synchronize_rcu_bh_expedited(void)
82{
83 synchronize_sched_expedited();
84}
85
86extern void __rcu_init(void);
87extern void rcu_check_callbacks(int cpu, int user);
88
89extern long rcu_batches_completed(void);
90extern long rcu_batches_completed_bh(void);
91extern long rcu_batches_completed_sched(void);
92
93#ifdef CONFIG_NO_HZ
94void rcu_enter_nohz(void);
95void rcu_exit_nohz(void);
96#else /* CONFIG_NO_HZ */
97static inline void rcu_enter_nohz(void)
98{
99}
100static inline void rcu_exit_nohz(void)
101{
102}
103#endif /* CONFIG_NO_HZ */
104
105/* A context switch is a grace period for RCU-sched and RCU-bh. */
106static inline int rcu_blocking_is_gp(void)
107{
108 return num_online_cpus() == 1;
109}
110
111#endif /* __LINUX_RCUTREE_H */