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Diffstat (limited to 'include/linux/rcutree.h')
| -rw-r--r-- | include/linux/rcutree.h | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h new file mode 100644 index 00000000000..8044b1b9433 --- /dev/null +++ b/include/linux/rcutree.h @@ -0,0 +1,121 @@ +/* + * Read-Copy Update mechanism for mutual exclusion (tree-based version) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2008 + * + * Author: Dipankar Sarma <dipankar@in.ibm.com> + * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm + * + * Based on the original work by Paul McKenney <paulmck@us.ibm.com> + * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen. + * + * For detailed explanation of Read-Copy Update mechanism see - + * Documentation/RCU + */ + +#ifndef __LINUX_RCUTREE_H +#define __LINUX_RCUTREE_H + +struct notifier_block; + +extern void rcu_sched_qs(int cpu); +extern void rcu_bh_qs(int cpu); +extern int rcu_needs_cpu(int cpu); +extern void rcu_scheduler_starting(void); +extern int rcu_expedited_torture_stats(char *page); + +#ifdef CONFIG_TREE_PREEMPT_RCU + +extern void __rcu_read_lock(void); +extern void __rcu_read_unlock(void); +extern void synchronize_rcu(void); +extern void exit_rcu(void); + +/* + * Defined as macro as it is a very low level header + * included from areas that don't even know about current + */ +#define rcu_preempt_depth() (current->rcu_read_lock_nesting) + +#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */ + +static inline void __rcu_read_lock(void) +{ + preempt_disable(); +} + +static inline void __rcu_read_unlock(void) +{ + preempt_enable(); +} + +#define synchronize_rcu synchronize_sched + +static inline void exit_rcu(void) +{ +} + +static inline int rcu_preempt_depth(void) +{ + return 0; +} + +#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */ + +static inline void __rcu_read_lock_bh(void) +{ + local_bh_disable(); +} +static inline void __rcu_read_unlock_bh(void) +{ + local_bh_enable(); +} + +extern void call_rcu_sched(struct rcu_head *head, + void (*func)(struct rcu_head *rcu)); +extern void synchronize_rcu_expedited(void); + +static inline void synchronize_rcu_bh_expedited(void) +{ + synchronize_sched_expedited(); +} + +extern void rcu_check_callbacks(int cpu, int user); + +extern long rcu_batches_completed(void); +extern long rcu_batches_completed_bh(void); +extern long rcu_batches_completed_sched(void); + +#ifdef CONFIG_NO_HZ +void rcu_enter_nohz(void); +void rcu_exit_nohz(void); +#else /* CONFIG_NO_HZ */ +static inline void rcu_enter_nohz(void) +{ +} +static inline void rcu_exit_nohz(void) +{ +} +#endif /* CONFIG_NO_HZ */ + +/* A context switch is a grace period for RCU-sched and RCU-bh. */ +static inline int rcu_blocking_is_gp(void) +{ + return num_online_cpus() == 1; +} + +#endif /* __LINUX_RCUTREE_H */ |