| | 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 | |
| | 33 | struct notifier_block; |
| | 34 | |
| | 35 | extern void rcu_sched_qs(int cpu); |
| | 36 | extern void rcu_bh_qs(int cpu); |
| | 37 | extern int rcu_cpu_notify(struct notifier_block *self, |
| | 38 | unsigned long action, void *hcpu); |
| | 39 | extern int rcu_needs_cpu(int cpu); |
| | 40 | extern int rcu_expedited_torture_stats(char *page); |
| | 41 | |
| | 42 | #ifdef CONFIG_TREE_PREEMPT_RCU |
| | 43 | |
| | 44 | extern void __rcu_read_lock(void); |
| | 45 | extern void __rcu_read_unlock(void); |
| | 46 | extern void exit_rcu(void); |
| | 47 | |
| | 48 | #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ |
| | 49 | |
| | 50 | static inline void __rcu_read_lock(void) |
| | 51 | { |
| | 52 | preempt_disable(); |
| | 53 | } |
| | 54 | |
| | 55 | static inline void __rcu_read_unlock(void) |
| | 56 | { |
| | 57 | preempt_enable(); |
| | 58 | } |
| | 59 | |
| | 60 | #define __synchronize_sched() synchronize_rcu() |
| | 61 | |
| | 62 | static inline void exit_rcu(void) |
| | 63 | { |
| | 64 | } |
| | 65 | |
| | 66 | #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ |
| | 67 | |
| | 68 | static inline void __rcu_read_lock_bh(void) |
| | 69 | { |
| | 70 | local_bh_disable(); |
| | 71 | } |
| | 72 | static inline void __rcu_read_unlock_bh(void) |
| | 73 | { |
| | 74 | local_bh_enable(); |
| | 75 | } |
| | 76 | |
| | 77 | extern void call_rcu_sched(struct rcu_head *head, |
| | 78 | void (*func)(struct rcu_head *rcu)); |
| | 79 | |
| | 80 | static inline void synchronize_rcu_expedited(void) |
| | 81 | { |
| | 82 | synchronize_sched_expedited(); |
| | 83 | } |
| | 84 | |
| | 85 | static inline void synchronize_rcu_bh_expedited(void) |
| | 86 | { |
| | 87 | synchronize_sched_expedited(); |
| | 88 | } |
| | 89 | |
| | 90 | extern void __rcu_init(void); |
| | 91 | extern void rcu_check_callbacks(int cpu, int user); |
| | 92 | |
| | 93 | extern long rcu_batches_completed(void); |
| | 94 | extern long rcu_batches_completed_bh(void); |
| | 95 | extern long rcu_batches_completed_sched(void); |
| | 96 | |
| | 97 | #ifdef CONFIG_NO_HZ |
| | 98 | void rcu_enter_nohz(void); |
| | 99 | void rcu_exit_nohz(void); |
| | 100 | #else /* CONFIG_NO_HZ */ |
| | 101 | static inline void rcu_enter_nohz(void) |
| | 102 | { |
| | 103 | } |
| | 104 | static inline void rcu_exit_nohz(void) |
| | 105 | { |
| | 106 | } |
| | 107 | #endif /* CONFIG_NO_HZ */ |
| | 108 | |
| | 109 | /* A context switch is a grace period for RCU-sched and RCU-bh. */ |
| | 110 | static inline int rcu_blocking_is_gp(void) |
| | 111 | { |
| | 112 | return num_online_cpus() == 1; |
| | 113 | } |
| | 114 | |
| | 115 | #endif /* __LINUX_RCUTREE_H */ |
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