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 #define rcu_init_sched() do { } while (0) 31 32 #ifdef CONFIG_TINY_RCU 33 34 static inline void synchronize_rcu_expedited(void) 35 { 36 synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */ 37 } 38 39 static inline void rcu_barrier(void) 40 { 41 rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ 42 } 43 44 #else /* #ifdef CONFIG_TINY_RCU */ 45 46 void rcu_barrier(void); 47 void synchronize_rcu_expedited(void); 48 49 #endif /* #else #ifdef CONFIG_TINY_RCU */ 50 51 static inline void synchronize_rcu_bh(void) 52 { 53 synchronize_sched(); 54 } 55 56 static inline void synchronize_rcu_bh_expedited(void) 57 { 58 synchronize_sched(); 59 } 60 61 #ifdef CONFIG_TINY_RCU 62 63 static inline void rcu_preempt_note_context_switch(void) 64 { 65 } 66 67 static inline void exit_rcu(void) 68 { 69 } 70 71 static inline int rcu_needs_cpu(int cpu) 72 { 73 return 0; 74 } 75 76 #else /* #ifdef CONFIG_TINY_RCU */ 77 78 void rcu_preempt_note_context_switch(void); 79 extern void exit_rcu(void); 80 int rcu_preempt_needs_cpu(void); 81 82 static inline int rcu_needs_cpu(int cpu) 83 { 84 return rcu_preempt_needs_cpu(); 85 } 86 87 #endif /* #else #ifdef CONFIG_TINY_RCU */ 88 89 static inline void rcu_note_context_switch(int cpu) 90 { 91 rcu_sched_qs(cpu); 92 rcu_preempt_note_context_switch(); 93 } 94 95 /* 96 * Return the number of grace periods. 97 */ 98 static inline long rcu_batches_completed(void) 99 { 100 return 0; 101 } 102 103 /* 104 * Return the number of bottom-half grace periods. 105 */ 106 static inline long rcu_batches_completed_bh(void) 107 { 108 return 0; 109 } 110 111 static inline void rcu_force_quiescent_state(void) 112 { 113 } 114 115 static inline void rcu_bh_force_quiescent_state(void) 116 { 117 } 118 119 static inline void rcu_sched_force_quiescent_state(void) 120 { 121 } 122 123 static inline void rcu_cpu_stall_reset(void) 124 { 125 } 126 127 #ifdef CONFIG_DEBUG_LOCK_ALLOC 128 129 extern int rcu_scheduler_active __read_mostly; 130 extern void rcu_scheduler_starting(void); 131 132 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 133 134 static inline void rcu_scheduler_starting(void) 135 { 136 } 137 138 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */ 139 140 #endif /* __LINUX_RCUTINY_H */ 141