include/linux/rcutree.h

   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 extern void rcu_note_context_switch(int cpu);
  34 extern int rcu_needs_cpu(int cpu);
  35 extern void rcu_cpu_stall_reset(void);
  36
  37 #ifdef CONFIG_TREE_PREEMPT_RCU
  38
  39 extern void exit_rcu(void);
  40
  41 #else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
  42
  43 static inline void exit_rcu(void)
  44 {
  45 }
  46
  47 #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
  48
  49 extern void synchronize_rcu_bh(void);
  50 extern void synchronize_rcu_expedited(void);
  51
  52 static inline void synchronize_rcu_bh_expedited(void)
  53 {
  54         synchronize_sched_expedited();
  55 }
  56
  57 extern void rcu_barrier(void);
  58
  59 extern long rcu_batches_completed(void);
  60 extern long rcu_batches_completed_bh(void);
  61 extern long rcu_batches_completed_sched(void);
  62 extern void rcu_force_quiescent_state(void);
  63 extern void rcu_bh_force_quiescent_state(void);
  64 extern void rcu_sched_force_quiescent_state(void);
  65
  66 /* A context switch is a grace period for RCU-sched and RCU-bh. */
  67 static inline int rcu_blocking_is_gp(void)
  68 {
  69         return num_online_cpus() == 1;
  70 }
  71
  72 extern void rcu_scheduler_starting(void);
  73 extern int rcu_scheduler_active __read_mostly;
  74
  75 #endif /* __LINUX_RCUTREE_H */