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 static inline void rcu_init(void) 31 { 32 } 33 34 #ifdef CONFIG_TINY_RCU 35 36 static inline void synchronize_rcu_expedited(void) 37 { 38 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ 39 } 40 41 static inline void rcu_barrier(void) 42 { 43 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ 44 } 45 46 #else /* #ifdef CONFIG_TINY_RCU */ 47 48 void rcu_barrier(void); 49 void synchronize_rcu_expedited(void); 50 51 #endif /* #else #ifdef CONFIG_TINY_RCU */ 52 53 static inline void synchronize_rcu_bh(void) 54 { 55 synchronize_sched(); 56 } 57 58 static inline void synchronize_rcu_bh_expedited(void) 59 { 60 synchronize_sched(); 61 } 62 63 static inline void synchronize_sched_expedited(void) 64 { 65 synchronize_sched(); 66 } 67 68 #ifdef CONFIG_TINY_RCU 69 70 static inline void rcu_preempt_note_context_switch(void) 71 { 72 } 73 74 static inline void exit_rcu(void) 75 { 76 } 77 78 static inline int rcu_needs_cpu(int cpu) 79 { 80 return 0; 81 } 82 83 #else /* #ifdef CONFIG_TINY_RCU */ 84 85 void rcu_preempt_note_context_switch(void); 86 extern void exit_rcu(void); 87 int rcu_preempt_needs_cpu(void); 88 89 static inline int rcu_needs_cpu(int cpu) 90 { 91 return rcu_preempt_needs_cpu(); 92 } 93 94 #endif /* #else #ifdef CONFIG_TINY_RCU */ 95 96 static inline void rcu_note_context_switch(int cpu) 97 { 98 rcu_sched_qs(cpu); 99 rcu_preempt_note_context_switch(); 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. 112 */ 113 static inline long rcu_batches_completed(void) 114 { 115 return 0; 116 } 117 118 /* 119 * Return the number of bottom-half grace periods. 120 */ 121 static inline long rcu_batches_completed_bh(void) 122 { 123 return 0; 124 } 125 126 static inline void rcu_force_quiescent_state(void) 127 { 128 } 129 130 static inline void rcu_bh_force_quiescent_state(void) 131 { 132 } 133 134 static inline void rcu_sched_force_quiescent_state(void) 135 { 136 } 137 138 static inline void rcu_cpu_stall_reset(void) 139 { 140 } 141 142 #ifdef CONFIG_DEBUG_LOCK_ALLOC 143 extern int rcu_scheduler_active __read_mostly; 144 extern void rcu_scheduler_starting(void); 145 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 146 static inline void rcu_scheduler_starting(void) 147 { 148 } 149 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 150 151 #endif /* __LINUX_RCUTINY_H */ 152