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 <[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 #ifdef CONFIG_RCU_BOOST 31 static inline void rcu_init(void) 32 { 33 } 34 #else /* #ifdef CONFIG_RCU_BOOST */ 35 void rcu_init(void); 36 #endif /* #else #ifdef CONFIG_RCU_BOOST */ 37 38 static inline void rcu_barrier_bh(void) 39 { 40 wait_rcu_gp(call_rcu_bh); 41 } 42 43 static inline void rcu_barrier_sched(void) 44 { 45 wait_rcu_gp(call_rcu_sched); 46 } 47 48 #ifdef CONFIG_TINY_RCU 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 #else /* #ifdef CONFIG_TINY_RCU */ 61 62 void synchronize_rcu_expedited(void); 63 64 static inline void rcu_barrier(void) 65 { 66 wait_rcu_gp(call_rcu); 67 } 68 69 #endif /* #else #ifdef CONFIG_TINY_RCU */ 70 71 static inline void synchronize_rcu_bh(void) 72 { 73 synchronize_sched(); 74 } 75 76 static inline void synchronize_rcu_bh_expedited(void) 77 { 78 synchronize_sched(); 79 } 80 81 static inline void synchronize_sched_expedited(void) 82 { 83 synchronize_sched(); 84 } 85 86 #ifdef CONFIG_TINY_RCU 87 88 static inline void rcu_preempt_note_context_switch(void) 89 { 90 } 91 92 static inline void exit_rcu(void) 93 { 94 } 95 96 static inline int rcu_needs_cpu(int cpu) 97 { 98 return 0; 99 } 100 101 #else /* #ifdef CONFIG_TINY_RCU */ 102 103 void rcu_preempt_note_context_switch(void); 104 extern void exit_rcu(void); 105 int rcu_preempt_needs_cpu(void); 106 107 static inline int rcu_needs_cpu(int cpu) 108 { 109 return rcu_preempt_needs_cpu(); 110 } 111 112 #endif /* #else #ifdef CONFIG_TINY_RCU */ 113 114 static inline void rcu_note_context_switch(int cpu) 115 { 116 rcu_sched_qs(cpu); 117 rcu_preempt_note_context_switch(); 118 } 119 120 /* 121 * Take advantage of the fact that there is only one CPU, which 122 * allows us to ignore virtualization-based context switches. 123 */ 124 static inline void rcu_virt_note_context_switch(int cpu) 125 { 126 } 127 128 /* 129 * Return the number of grace periods. 130 */ 131 static inline long rcu_batches_completed(void) 132 { 133 return 0; 134 } 135 136 /* 137 * Return the number of bottom-half grace periods. 138 */ 139 static inline long rcu_batches_completed_bh(void) 140 { 141 return 0; 142 } 143 144 static inline void rcu_force_quiescent_state(void) 145 { 146 } 147 148 static inline void rcu_bh_force_quiescent_state(void) 149 { 150 } 151 152 static inline void rcu_sched_force_quiescent_state(void) 153 { 154 } 155 156 static inline void rcu_cpu_stall_reset(void) 157 { 158 } 159 160 #ifdef CONFIG_DEBUG_LOCK_ALLOC 161 extern int rcu_scheduler_active __read_mostly; 162 extern void rcu_scheduler_starting(void); 163 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 164 static inline void rcu_scheduler_starting(void) 165 { 166 } 167 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 168 169 #endif /* __LINUX_RCUTINY_H */ 170