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 static inline void rcu_note_context_switch(int cpu)
  33 {
  34         rcu_sched_qs(cpu);
  35 }
  36
  37 #define __rcu_read_lock()       preempt_disable()
  38 #define __rcu_read_unlock()     preempt_enable()
  39 #define __rcu_read_lock_bh()    local_bh_disable()
  40 #define __rcu_read_unlock_bh()  local_bh_enable()
  41 #define call_rcu_sched          call_rcu
  42
  43 #define rcu_init_sched()        do { } while (0)
  44 extern void rcu_check_callbacks(int cpu, int user);
  45
  46 static inline int rcu_needs_cpu(int cpu)
  47 {
  48         return 0;
  49 }
  50
  51 /*
  52  * Return the number of grace periods.
  53  */
  54 static inline long rcu_batches_completed(void)
  55 {
  56         return 0;
  57 }
  58
  59 /*
  60  * Return the number of bottom-half grace periods.
  61  */
  62 static inline long rcu_batches_completed_bh(void)
  63 {
  64         return 0;
  65 }
  66
  67 static inline void rcu_force_quiescent_state(void)
  68 {
  69 }
  70
  71 static inline void rcu_bh_force_quiescent_state(void)
  72 {
  73 }
  74
  75 static inline void rcu_sched_force_quiescent_state(void)
  76 {
  77 }
  78
  79 extern void synchronize_sched(void);
  80
  81 static inline void synchronize_rcu(void)
  82 {
  83         synchronize_sched();
  84 }
  85
  86 static inline void synchronize_rcu_bh(void)
  87 {
  88         synchronize_sched();
  89 }
  90
  91 static inline void synchronize_rcu_expedited(void)
  92 {
  93         synchronize_sched();
  94 }
  95
  96 static inline void synchronize_rcu_bh_expedited(void)
  97 {
  98         synchronize_sched();
  99 }
 100
 101 struct notifier_block;
 102
 103 #ifdef CONFIG_NO_HZ
 104
 105 extern void rcu_enter_nohz(void);
 106 extern void rcu_exit_nohz(void);
 107
 108 #else /* #ifdef CONFIG_NO_HZ */
 109
 110 static inline void rcu_enter_nohz(void)
 111 {
 112 }
 113
 114 static inline void rcu_exit_nohz(void)
 115 {
 116 }
 117
 118 #endif /* #else #ifdef CONFIG_NO_HZ */
 119
 120 static inline void exit_rcu(void)
 121 {
 122 }
 123
 124 static inline int rcu_preempt_depth(void)
 125 {
 126         return 0;
 127 }
 128
 129 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 130
 131 extern int rcu_scheduler_active __read_mostly;
 132 extern void rcu_scheduler_starting(void);
 133
 134 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 135
 136 static inline void rcu_scheduler_starting(void)
 137 {
 138 }
 139
 140 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 141
 142 #endif /* __LINUX_RCUTINY_H */