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 #define rcu_init_sched()        do { } while (0)
  31
  32 #ifdef CONFIG_TINY_RCU
  33
  34 static inline void synchronize_rcu_expedited(void)
  35 {
  36         synchronize_sched();    /* Only one CPU, so pretty fast anyway!!! */
  37 }
  38
  39 static inline void rcu_barrier(void)
  40 {
  41         rcu_barrier_sched();  /* Only one CPU, so only one list of callbacks! */
  42 }
  43
  44 #else /* #ifdef CONFIG_TINY_RCU */
  45
  46 void rcu_barrier(void);
  47 void synchronize_rcu_expedited(void);
  48
  49 #endif /* #else #ifdef CONFIG_TINY_RCU */
  50
  51 static inline void synchronize_rcu_bh(void)
  52 {
  53         synchronize_sched();
  54 }
  55
  56 static inline void synchronize_rcu_bh_expedited(void)
  57 {
  58         synchronize_sched();
  59 }
  60
  61 #ifdef CONFIG_TINY_RCU
  62
  63 static inline void rcu_preempt_note_context_switch(void)
  64 {
  65 }
  66
  67 static inline void exit_rcu(void)
  68 {
  69 }
  70
  71 static inline int rcu_needs_cpu(int cpu)
  72 {
  73         return 0;
  74 }
  75
  76 #else /* #ifdef CONFIG_TINY_RCU */
  77
  78 void rcu_preempt_note_context_switch(void);
  79 extern void exit_rcu(void);
  80 int rcu_preempt_needs_cpu(void);
  81
  82 static inline int rcu_needs_cpu(int cpu)
  83 {
  84         return rcu_preempt_needs_cpu();
  85 }
  86
  87 #endif /* #else #ifdef CONFIG_TINY_RCU */
  88
  89 static inline void rcu_note_context_switch(int cpu)
  90 {
  91         rcu_sched_qs(cpu);
  92         rcu_preempt_note_context_switch();
  93 }
  94
  95 /*
  96  * Return the number of grace periods.
  97  */
  98 static inline long rcu_batches_completed(void)
  99 {
 100         return 0;
 101 }
 102
 103 /*
 104  * Return the number of bottom-half grace periods.
 105  */
 106 static inline long rcu_batches_completed_bh(void)
 107 {
 108         return 0;
 109 }
 110
 111 static inline void rcu_force_quiescent_state(void)
 112 {
 113 }
 114
 115 static inline void rcu_bh_force_quiescent_state(void)
 116 {
 117 }
 118
 119 static inline void rcu_sched_force_quiescent_state(void)
 120 {
 121 }
 122
 123 static inline void rcu_cpu_stall_reset(void)
 124 {
 125 }
 126
 127 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 128
 129 extern int rcu_scheduler_active __read_mostly;
 130 extern void rcu_scheduler_starting(void);
 131
 132 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 133
 134 static inline void rcu_scheduler_starting(void)
 135 {
 136 }
 137
 138 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 139
 140 #endif /* __LINUX_RCUTINY_H */