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 <[email protected]> 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 struct rcu_dynticks; 31 static inline int rcu_dynticks_snap(struct rcu_dynticks *rdtp) 32 { 33 return 0; 34 } 35 36 static inline unsigned long get_state_synchronize_rcu(void) 37 { 38 return 0; 39 } 40 41 static inline void cond_synchronize_rcu(unsigned long oldstate) 42 { 43 might_sleep(); 44 } 45 46 static inline unsigned long get_state_synchronize_sched(void) 47 { 48 return 0; 49 } 50 51 static inline void cond_synchronize_sched(unsigned long oldstate) 52 { 53 might_sleep(); 54 } 55 56 static inline void rcu_barrier_bh(void) 57 { 58 wait_rcu_gp(call_rcu_bh); 59 } 60 61 static inline void rcu_barrier_sched(void) 62 { 63 wait_rcu_gp(call_rcu_sched); 64 } 65 66 static inline void synchronize_rcu_expedited(void) 67 { 68 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ 69 } 70 71 static inline void rcu_barrier(void) 72 { 73 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ 74 } 75 76 static inline void synchronize_rcu_bh(void) 77 { 78 synchronize_sched(); 79 } 80 81 static inline void synchronize_rcu_bh_expedited(void) 82 { 83 synchronize_sched(); 84 } 85 86 static inline void synchronize_sched_expedited(void) 87 { 88 synchronize_sched(); 89 } 90 91 static inline void kfree_call_rcu(struct rcu_head *head, 92 rcu_callback_t func) 93 { 94 call_rcu(head, func); 95 } 96 97 static inline void rcu_note_context_switch(void) 98 { 99 rcu_sched_qs(); 100 } 101 102 /* 103 * Take advantage of the fact that there is only one CPU, which 104 * allows us to ignore virtualization-based context switches. 105 */ 106 static inline void rcu_virt_note_context_switch(int cpu) 107 { 108 } 109 110 /* 111 * Return the number of grace periods started. 112 */ 113 static inline unsigned long rcu_batches_started(void) 114 { 115 return 0; 116 } 117 118 /* 119 * Return the number of bottom-half grace periods started. 120 */ 121 static inline unsigned long rcu_batches_started_bh(void) 122 { 123 return 0; 124 } 125 126 /* 127 * Return the number of sched grace periods started. 128 */ 129 static inline unsigned long rcu_batches_started_sched(void) 130 { 131 return 0; 132 } 133 134 /* 135 * Return the number of grace periods completed. 136 */ 137 static inline unsigned long rcu_batches_completed(void) 138 { 139 return 0; 140 } 141 142 /* 143 * Return the number of bottom-half grace periods completed. 144 */ 145 static inline unsigned long rcu_batches_completed_bh(void) 146 { 147 return 0; 148 } 149 150 /* 151 * Return the number of sched grace periods completed. 152 */ 153 static inline unsigned long rcu_batches_completed_sched(void) 154 { 155 return 0; 156 } 157 158 /* 159 * Return the number of expedited grace periods completed. 160 */ 161 static inline unsigned long rcu_exp_batches_completed(void) 162 { 163 return 0; 164 } 165 166 /* 167 * Return the number of expedited sched grace periods completed. 168 */ 169 static inline unsigned long rcu_exp_batches_completed_sched(void) 170 { 171 return 0; 172 } 173 174 static inline void rcu_force_quiescent_state(void) 175 { 176 } 177 178 static inline void rcu_bh_force_quiescent_state(void) 179 { 180 } 181 182 static inline void rcu_sched_force_quiescent_state(void) 183 { 184 } 185 186 static inline void show_rcu_gp_kthreads(void) 187 { 188 } 189 190 static inline void rcu_cpu_stall_reset(void) 191 { 192 } 193 194 static inline void rcu_idle_enter(void) 195 { 196 } 197 198 static inline void rcu_idle_exit(void) 199 { 200 } 201 202 static inline void rcu_irq_enter(void) 203 { 204 } 205 206 static inline void rcu_irq_exit_irqson(void) 207 { 208 } 209 210 static inline void rcu_irq_enter_irqson(void) 211 { 212 } 213 214 static inline void rcu_irq_exit(void) 215 { 216 } 217 218 static inline void exit_rcu(void) 219 { 220 } 221 222 #ifdef CONFIG_DEBUG_LOCK_ALLOC 223 extern int rcu_scheduler_active __read_mostly; 224 void rcu_scheduler_starting(void); 225 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 226 static inline void rcu_scheduler_starting(void) 227 { 228 } 229 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 230 231 #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) 232 233 static inline bool rcu_is_watching(void) 234 { 235 return __rcu_is_watching(); 236 } 237 238 #else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ 239 240 static inline bool rcu_is_watching(void) 241 { 242 return true; 243 } 244 245 #endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */ 246 247 static inline void rcu_all_qs(void) 248 { 249 barrier(); /* Avoid RCU read-side critical sections leaking across. */ 250 } 251 252 /* RCUtree hotplug events */ 253 #define rcutree_prepare_cpu NULL 254 #define rcutree_online_cpu NULL 255 #define rcutree_offline_cpu NULL 256 #define rcutree_dead_cpu NULL 257 #define rcutree_dying_cpu NULL 258 259 #endif /* __LINUX_RCUTINY_H */ 260