2 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
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.
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.
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.
18 * Copyright IBM Corporation, 2008
20 * Author: Dipankar Sarma <dipankar@in.ibm.com>
21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
26 * For detailed explanation of Read-Copy Update mechanism see -
30 #ifndef __LINUX_RCUTREE_H
31 #define __LINUX_RCUTREE_H
33 extern void rcu_sched_qs(int cpu);
34 extern void rcu_bh_qs(int cpu);
36 extern int rcu_pending(int cpu);
37 extern int rcu_needs_cpu(int cpu);
39 static inline void __rcu_read_lock(void)
43 static inline void __rcu_read_unlock(void)
47 static inline void __rcu_read_lock_bh(void)
51 static inline void __rcu_read_unlock_bh(void)
56 #define __synchronize_sched() synchronize_rcu()
58 extern void call_rcu_sched(struct rcu_head *head,
59 void (*func)(struct rcu_head *rcu));
61 static inline void synchronize_rcu_expedited(void)
63 synchronize_sched_expedited();
66 static inline void synchronize_rcu_bh_expedited(void)
68 synchronize_sched_expedited();
71 extern void __rcu_init(void);
72 extern void rcu_check_callbacks(int cpu, int user);
73 extern void rcu_restart_cpu(int cpu);
75 extern long rcu_batches_completed(void);
76 extern long rcu_batches_completed_bh(void);
77 extern long rcu_batches_completed_sched(void);
79 static inline void rcu_init_sched(void)
84 void rcu_enter_nohz(void);
85 void rcu_exit_nohz(void);
86 #else /* CONFIG_NO_HZ */
87 static inline void rcu_enter_nohz(void)
90 static inline void rcu_exit_nohz(void)
93 #endif /* CONFIG_NO_HZ */
95 /* A context switch is a grace period for rcutree. */
96 static inline int rcu_blocking_is_gp(void)
98 return num_online_cpus() == 1;
101 #endif /* __LINUX_RCUTREE_H */