/* * 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 void rcu_note_context_switch(int cpu); extern int rcu_needs_cpu(int cpu); #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_bh(void); extern void synchronize_sched(void); 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); extern void rcu_force_quiescent_state(void); extern void rcu_bh_force_quiescent_state(void); extern void rcu_sched_force_quiescent_state(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; } extern void rcu_scheduler_starting(void); extern int rcu_scheduler_active __read_mostly; #endif /* __LINUX_RCUTREE_H */