include/linux/rcutiny.h

   1 /*
   2  * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
   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: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  21  *
  22  * For detailed explanation of Read-Copy Update mechanism see -
  23  *              Documentation/RCU
  24  */
  25 #ifndef __LINUX_TINY_H
  26 #define __LINUX_TINY_H
  27
  28 #include <linux/cache.h>
  29
  30 void rcu_sched_qs(int cpu);
  31 void rcu_bh_qs(int cpu);
  32
  33 #define __rcu_read_lock()       preempt_disable()
  34 #define __rcu_read_unlock()     preempt_enable()
  35 #define __rcu_read_lock_bh()    local_bh_disable()
  36 #define __rcu_read_unlock_bh()  local_bh_enable()
  37 #define call_rcu_sched          call_rcu
  38
  39 #define rcu_init_sched()        do { } while (0)
  40 extern void rcu_check_callbacks(int cpu, int user);
  41
  42 static inline int rcu_needs_cpu(int cpu)
  43 {
  44         return 0;
  45 }
  46
  47 /*
  48  * Return the number of grace periods.
  49  */
  50 static inline long rcu_batches_completed(void)
  51 {
  52         return 0;
  53 }
  54
  55 /*
  56  * Return the number of bottom-half grace periods.
  57  */
  58 static inline long rcu_batches_completed_bh(void)
  59 {
  60         return 0;
  61 }
  62
  63 extern int rcu_expedited_torture_stats(char *page);
  64
  65 static inline void rcu_force_quiescent_state(void)
  66 {
  67 }
  68
  69 static inline void rcu_bh_force_quiescent_state(void)
  70 {
  71 }
  72
  73 static inline void rcu_sched_force_quiescent_state(void)
  74 {
  75 }
  76
  77 #define synchronize_rcu synchronize_sched
  78
  79 static inline void synchronize_rcu_expedited(void)
  80 {
  81         synchronize_sched();
  82 }
  83
  84 static inline void synchronize_rcu_bh_expedited(void)
  85 {
  86         synchronize_sched();
  87 }
  88
  89 struct notifier_block;
  90
  91 #ifdef CONFIG_NO_HZ
  92
  93 extern void rcu_enter_nohz(void);
  94 extern void rcu_exit_nohz(void);
  95
  96 #else /* #ifdef CONFIG_NO_HZ */
  97
  98 static inline void rcu_enter_nohz(void)
  99 {
 100 }
 101
 102 static inline void rcu_exit_nohz(void)
 103 {
 104 }
 105
 106 #endif /* #else #ifdef CONFIG_NO_HZ */
 107
 108 static inline void exit_rcu(void)
 109 {
 110 }
 111
 112 static inline int rcu_preempt_depth(void)
 113 {
 114         return 0;
 115 }
 116
 117 #endif /* __LINUX_RCUTINY_H */