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 unsigned long get_state_synchronize_sched(void)
  41 {
  42         return 0;
  43 }
  44
  45 static inline void cond_synchronize_sched(unsigned long oldstate)
  46 {
  47         might_sleep();
  48 }
  49
  50 static inline void rcu_barrier_bh(void)
  51 {
  52         wait_rcu_gp(call_rcu_bh);
  53 }
  54
  55 static inline void rcu_barrier_sched(void)
  56 {
  57         wait_rcu_gp(call_rcu_sched);
  58 }
  59
  60 static inline void synchronize_rcu_expedited(void)
  61 {
  62         synchronize_sched();    /* Only one CPU, so pretty fast anyway!!! */
  63 }
  64
  65 static inline void rcu_barrier(void)
  66 {
  67         rcu_barrier_sched();  /* Only one CPU, so only one list of callbacks! */
  68 }
  69
  70 static inline void synchronize_rcu_bh(void)
  71 {
  72         synchronize_sched();
  73 }
  74
  75 static inline void synchronize_rcu_bh_expedited(void)
  76 {
  77         synchronize_sched();
  78 }
  79
  80 static inline void synchronize_sched_expedited(void)
  81 {
  82         synchronize_sched();
  83 }
  84
  85 static inline void kfree_call_rcu(struct rcu_head *head,
  86                                   rcu_callback_t func)
  87 {
  88         call_rcu(head, func);
  89 }
  90
  91 static inline void rcu_note_context_switch(void)
  92 {
  93         rcu_sched_qs();
  94 }
  95
  96 /*
  97  * Take advantage of the fact that there is only one CPU, which
  98  * allows us to ignore virtualization-based context switches.
  99  */
 100 static inline void rcu_virt_note_context_switch(int cpu)
 101 {
 102 }
 103
 104 /*
 105  * Return the number of grace periods started.
 106  */
 107 static inline unsigned long rcu_batches_started(void)
 108 {
 109         return 0;
 110 }
 111
 112 /*
 113  * Return the number of bottom-half grace periods started.
 114  */
 115 static inline unsigned long rcu_batches_started_bh(void)
 116 {
 117         return 0;
 118 }
 119
 120 /*
 121  * Return the number of sched grace periods started.
 122  */
 123 static inline unsigned long rcu_batches_started_sched(void)
 124 {
 125         return 0;
 126 }
 127
 128 /*
 129  * Return the number of grace periods completed.
 130  */
 131 static inline unsigned long rcu_batches_completed(void)
 132 {
 133         return 0;
 134 }
 135
 136 /*
 137  * Return the number of bottom-half grace periods completed.
 138  */
 139 static inline unsigned long rcu_batches_completed_bh(void)
 140 {
 141         return 0;
 142 }
 143
 144 /*
 145  * Return the number of sched grace periods completed.
 146  */
 147 static inline unsigned long rcu_batches_completed_sched(void)
 148 {
 149         return 0;
 150 }
 151
 152 /*
 153  * Return the number of expedited grace periods completed.
 154  */
 155 static inline unsigned long rcu_exp_batches_completed(void)
 156 {
 157         return 0;
 158 }
 159
 160 /*
 161  * Return the number of expedited sched grace periods completed.
 162  */
 163 static inline unsigned long rcu_exp_batches_completed_sched(void)
 164 {
 165         return 0;
 166 }
 167
 168 static inline void rcu_force_quiescent_state(void)
 169 {
 170 }
 171
 172 static inline void rcu_bh_force_quiescent_state(void)
 173 {
 174 }
 175
 176 static inline void rcu_sched_force_quiescent_state(void)
 177 {
 178 }
 179
 180 static inline void show_rcu_gp_kthreads(void)
 181 {
 182 }
 183
 184 static inline void rcu_cpu_stall_reset(void)
 185 {
 186 }
 187
 188 static inline void rcu_idle_enter(void)
 189 {
 190 }
 191
 192 static inline void rcu_idle_exit(void)
 193 {
 194 }
 195
 196 static inline void rcu_irq_enter(void)
 197 {
 198 }
 199
 200 static inline void rcu_irq_exit_irqson(void)
 201 {
 202 }
 203
 204 static inline void rcu_irq_enter_irqson(void)
 205 {
 206 }
 207
 208 static inline void rcu_irq_exit(void)
 209 {
 210 }
 211
 212 static inline void exit_rcu(void)
 213 {
 214 }
 215
 216 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 217 extern int rcu_scheduler_active __read_mostly;
 218 void rcu_scheduler_starting(void);
 219 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 220 static inline void rcu_scheduler_starting(void)
 221 {
 222 }
 223 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 224
 225 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
 226
 227 static inline bool rcu_is_watching(void)
 228 {
 229         return __rcu_is_watching();
 230 }
 231
 232 #else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
 233
 234 static inline bool rcu_is_watching(void)
 235 {
 236         return true;
 237 }
 238
 239 #endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
 240
 241 static inline void rcu_all_qs(void)
 242 {
 243         barrier(); /* Avoid RCU read-side critical sections leaking across. */
 244 }
 245
 246 /* RCUtree hotplug events */
 247 #define rcutree_prepare_cpu      NULL
 248 #define rcutree_online_cpu       NULL
 249 #define rcutree_offline_cpu      NULL
 250 #define rcutree_dead_cpu         NULL
 251 #define rcutree_dying_cpu        NULL
 252
 253 #endif /* __LINUX_RCUTINY_H */