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, you can access it online at
  16  * http://www.gnu.org/licenses/gpl-2.0.html.
  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 static inline unsigned long get_state_synchronize_rcu(void)
  31 {
  32         return 0;
  33 }
  34
  35 static inline void cond_synchronize_rcu(unsigned long oldstate)
  36 {
  37         might_sleep();
  38 }
  39
  40 static inline void rcu_barrier_bh(void)
  41 {
  42         wait_rcu_gp(call_rcu_bh);
  43 }
  44
  45 static inline void rcu_barrier_sched(void)
  46 {
  47         wait_rcu_gp(call_rcu_sched);
  48 }
  49
  50 static inline void synchronize_rcu_expedited(void)
  51 {
  52         synchronize_sched();    /* Only one CPU, so pretty fast anyway!!! */
  53 }
  54
  55 static inline void rcu_barrier(void)
  56 {
  57         rcu_barrier_sched();  /* Only one CPU, so only one list of callbacks! */
  58 }
  59
  60 static inline void synchronize_rcu_bh(void)
  61 {
  62         synchronize_sched();
  63 }
  64
  65 static inline void synchronize_rcu_bh_expedited(void)
  66 {
  67         synchronize_sched();
  68 }
  69
  70 static inline void synchronize_sched_expedited(void)
  71 {
  72         synchronize_sched();
  73 }
  74
  75 static inline void kfree_call_rcu(struct rcu_head *head,
  76                                   void (*func)(struct rcu_head *rcu))
  77 {
  78         call_rcu(head, func);
  79 }
  80
  81 static inline void rcu_note_context_switch(void)
  82 {
  83         rcu_sched_qs();
  84 }
  85
  86 /*
  87  * Take advantage of the fact that there is only one CPU, which
  88  * allows us to ignore virtualization-based context switches.
  89  */
  90 static inline void rcu_virt_note_context_switch(int cpu)
  91 {
  92 }
  93
  94 /*
  95  * Return the number of grace periods started.
  96  */
  97 static inline unsigned long rcu_batches_started(void)
  98 {
  99         return 0;
 100 }
 101
 102 /*
 103  * Return the number of bottom-half grace periods started.
 104  */
 105 static inline unsigned long rcu_batches_started_bh(void)
 106 {
 107         return 0;
 108 }
 109
 110 /*
 111  * Return the number of sched grace periods started.
 112  */
 113 static inline unsigned long rcu_batches_started_sched(void)
 114 {
 115         return 0;
 116 }
 117
 118 /*
 119  * Return the number of grace periods completed.
 120  */
 121 static inline unsigned long rcu_batches_completed(void)
 122 {
 123         return 0;
 124 }
 125
 126 /*
 127  * Return the number of bottom-half grace periods completed.
 128  */
 129 static inline unsigned long rcu_batches_completed_bh(void)
 130 {
 131         return 0;
 132 }
 133
 134 /*
 135  * Return the number of sched grace periods completed.
 136  */
 137 static inline unsigned long rcu_batches_completed_sched(void)
 138 {
 139         return 0;
 140 }
 141
 142 static inline void rcu_force_quiescent_state(void)
 143 {
 144 }
 145
 146 static inline void rcu_bh_force_quiescent_state(void)
 147 {
 148 }
 149
 150 static inline void rcu_sched_force_quiescent_state(void)
 151 {
 152 }
 153
 154 static inline void show_rcu_gp_kthreads(void)
 155 {
 156 }
 157
 158 static inline void rcu_cpu_stall_reset(void)
 159 {
 160 }
 161
 162 static inline void exit_rcu(void)
 163 {
 164 }
 165
 166 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 167 extern int rcu_scheduler_active __read_mostly;
 168 void rcu_scheduler_starting(void);
 169 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 170 static inline void rcu_scheduler_starting(void)
 171 {
 172 }
 173 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 174
 175 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
 176
 177 static inline bool rcu_is_watching(void)
 178 {
 179         return __rcu_is_watching();
 180 }
 181
 182 #else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
 183
 184 static inline bool rcu_is_watching(void)
 185 {
 186         return true;
 187 }
 188
 189 #endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
 190
 191 static inline void rcu_all_qs(void)
 192 {
 193 }
 194
 195 #endif /* __LINUX_RCUTINY_H */