Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 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 - |
Paul E. McKenney | a71fca5 | 2009-09-18 10:28:19 -0700 | [diff] [blame] | 27 | * Documentation/RCU |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 28 | */ |
| 29 | |
| 30 | #ifndef __LINUX_RCUTREE_H |
| 31 | #define __LINUX_RCUTREE_H |
| 32 | |
Paul E. McKenney | 9b2619a | 2009-09-23 09:50:43 -0700 | [diff] [blame] | 33 | struct notifier_block; |
| 34 | |
Paul E. McKenney | d6714c2 | 2009-08-22 13:56:46 -0700 | [diff] [blame] | 35 | extern void rcu_sched_qs(int cpu); |
| 36 | extern void rcu_bh_qs(int cpu); |
Paul E. McKenney | 25502a6 | 2010-04-01 17:37:01 -0700 | [diff] [blame] | 37 | extern void rcu_note_context_switch(int cpu); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 38 | extern int rcu_needs_cpu(int cpu); |
Paul E. McKenney | 53d84e0 | 2010-08-10 14:28:53 -0700 | [diff] [blame^] | 39 | extern void rcu_cpu_stall_reset(void); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 40 | |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 41 | #ifdef CONFIG_TREE_PREEMPT_RCU |
| 42 | |
| 43 | extern void __rcu_read_lock(void); |
| 44 | extern void __rcu_read_unlock(void); |
Paul E. McKenney | 6ebb237 | 2009-11-22 08:53:50 -0800 | [diff] [blame] | 45 | extern void synchronize_rcu(void); |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 46 | extern void exit_rcu(void); |
| 47 | |
Frederic Weisbecker | 234da7b | 2009-12-16 20:21:05 +0100 | [diff] [blame] | 48 | /* |
| 49 | * Defined as macro as it is a very low level header |
| 50 | * included from areas that don't even know about current |
| 51 | */ |
| 52 | #define rcu_preempt_depth() (current->rcu_read_lock_nesting) |
| 53 | |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 54 | #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ |
| 55 | |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 56 | static inline void __rcu_read_lock(void) |
| 57 | { |
| 58 | preempt_disable(); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 59 | } |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 60 | |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 61 | static inline void __rcu_read_unlock(void) |
| 62 | { |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 63 | preempt_enable(); |
| 64 | } |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 65 | |
Paul E. McKenney | 6ebb237 | 2009-11-22 08:53:50 -0800 | [diff] [blame] | 66 | #define synchronize_rcu synchronize_sched |
Paul E. McKenney | 16e3081 | 2009-09-13 09:15:11 -0700 | [diff] [blame] | 67 | |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 68 | static inline void exit_rcu(void) |
| 69 | { |
| 70 | } |
| 71 | |
Frederic Weisbecker | 234da7b | 2009-12-16 20:21:05 +0100 | [diff] [blame] | 72 | static inline int rcu_preempt_depth(void) |
| 73 | { |
| 74 | return 0; |
| 75 | } |
| 76 | |
Paul E. McKenney | f41d911 | 2009-08-22 13:56:52 -0700 | [diff] [blame] | 77 | #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ |
| 78 | |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 79 | static inline void __rcu_read_lock_bh(void) |
| 80 | { |
| 81 | local_bh_disable(); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 82 | } |
| 83 | static inline void __rcu_read_unlock_bh(void) |
| 84 | { |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 85 | local_bh_enable(); |
| 86 | } |
| 87 | |
Paul E. McKenney | d6714c2 | 2009-08-22 13:56:46 -0700 | [diff] [blame] | 88 | extern void call_rcu_sched(struct rcu_head *head, |
| 89 | void (*func)(struct rcu_head *rcu)); |
Paul E. McKenney | da848c4 | 2010-03-30 15:46:01 -0700 | [diff] [blame] | 90 | extern void synchronize_rcu_bh(void); |
| 91 | extern void synchronize_sched(void); |
Paul E. McKenney | 019129d5 | 2009-10-14 10:15:56 -0700 | [diff] [blame] | 92 | extern void synchronize_rcu_expedited(void); |
Paul E. McKenney | 03b042b | 2009-06-25 09:08:16 -0700 | [diff] [blame] | 93 | |
| 94 | static inline void synchronize_rcu_bh_expedited(void) |
| 95 | { |
| 96 | synchronize_sched_expedited(); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 97 | } |
| 98 | |
Paul E. McKenney | a57eb94 | 2010-06-29 16:49:16 -0700 | [diff] [blame] | 99 | extern void rcu_barrier(void); |
| 100 | |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 101 | extern void rcu_check_callbacks(int cpu, int user); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 102 | |
| 103 | extern long rcu_batches_completed(void); |
| 104 | extern long rcu_batches_completed_bh(void); |
Paul E. McKenney | d6714c2 | 2009-08-22 13:56:46 -0700 | [diff] [blame] | 105 | extern long rcu_batches_completed_sched(void); |
Paul E. McKenney | bf66f18 | 2010-01-04 15:09:10 -0800 | [diff] [blame] | 106 | extern void rcu_force_quiescent_state(void); |
| 107 | extern void rcu_bh_force_quiescent_state(void); |
| 108 | extern void rcu_sched_force_quiescent_state(void); |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 109 | |
| 110 | #ifdef CONFIG_NO_HZ |
| 111 | void rcu_enter_nohz(void); |
| 112 | void rcu_exit_nohz(void); |
| 113 | #else /* CONFIG_NO_HZ */ |
| 114 | static inline void rcu_enter_nohz(void) |
| 115 | { |
| 116 | } |
| 117 | static inline void rcu_exit_nohz(void) |
| 118 | { |
| 119 | } |
| 120 | #endif /* CONFIG_NO_HZ */ |
| 121 | |
Paul E. McKenney | 1eba8f8 | 2009-09-23 09:50:42 -0700 | [diff] [blame] | 122 | /* A context switch is a grace period for RCU-sched and RCU-bh. */ |
Paul E. McKenney | a682604 | 2009-02-25 18:03:42 -0800 | [diff] [blame] | 123 | static inline int rcu_blocking_is_gp(void) |
| 124 | { |
| 125 | return num_online_cpus() == 1; |
| 126 | } |
| 127 | |
Paul E. McKenney | bbad937 | 2010-04-02 16:17:17 -0700 | [diff] [blame] | 128 | extern void rcu_scheduler_starting(void); |
| 129 | extern int rcu_scheduler_active __read_mostly; |
| 130 | |
Paul E. McKenney | 64db4cf | 2008-12-18 21:55:32 +0100 | [diff] [blame] | 131 | #endif /* __LINUX_RCUTREE_H */ |