Linux 2.6.26-rc5
[linux-2.6/openmoko-kernel/knife-kernel.git] / include / linux / rcupreempt.h
blob8a05c7e20bc4e780c7765d34a2f9abda11436658
1 /*
2 * Read-Copy Update mechanism for mutual exclusion (RT implementation)
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.
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.
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.
18 * Copyright (C) IBM Corporation, 2006
20 * Author: Paul McKenney <paulmck@us.ibm.com>
22 * Based on the original work by Paul McKenney <paul.mckenney@us.ibm.com>
23 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
24 * Papers:
25 * http://www.rdrop.com/users/paulmck/paper/rclockpdcsproof.pdf
26 * http://lse.sourceforge.net/locking/rclock_OLS.2001.05.01c.sc.pdf (OLS2001)
28 * For detailed explanation of Read-Copy Update mechanism see -
29 * Documentation/RCU
33 #ifndef __LINUX_RCUPREEMPT_H
34 #define __LINUX_RCUPREEMPT_H
36 #include <linux/cache.h>
37 #include <linux/spinlock.h>
38 #include <linux/threads.h>
39 #include <linux/percpu.h>
40 #include <linux/cpumask.h>
41 #include <linux/seqlock.h>
43 #define rcu_qsctr_inc(cpu)
44 #define rcu_bh_qsctr_inc(cpu)
45 #define call_rcu_bh(head, rcu) call_rcu(head, rcu)
47 extern void __rcu_read_lock(void) __acquires(RCU);
48 extern void __rcu_read_unlock(void) __releases(RCU);
49 extern int rcu_pending(int cpu);
50 extern int rcu_needs_cpu(int cpu);
52 #define __rcu_read_lock_bh() { rcu_read_lock(); local_bh_disable(); }
53 #define __rcu_read_unlock_bh() { local_bh_enable(); rcu_read_unlock(); }
55 extern void __synchronize_sched(void);
57 extern void __rcu_init(void);
58 extern void rcu_check_callbacks(int cpu, int user);
59 extern void rcu_restart_cpu(int cpu);
60 extern long rcu_batches_completed(void);
63 * Return the number of RCU batches processed thus far. Useful for debug
64 * and statistic. The _bh variant is identifcal to straight RCU
66 static inline long rcu_batches_completed_bh(void)
68 return rcu_batches_completed();
71 #ifdef CONFIG_RCU_TRACE
72 struct rcupreempt_trace;
73 extern long *rcupreempt_flipctr(int cpu);
74 extern long rcupreempt_data_completed(void);
75 extern int rcupreempt_flip_flag(int cpu);
76 extern int rcupreempt_mb_flag(int cpu);
77 extern char *rcupreempt_try_flip_state_name(void);
78 extern struct rcupreempt_trace *rcupreempt_trace_cpu(int cpu);
79 #endif
81 struct softirq_action;
83 #ifdef CONFIG_NO_HZ
84 DECLARE_PER_CPU(long, dynticks_progress_counter);
86 static inline void rcu_enter_nohz(void)
88 smp_mb(); /* CPUs seeing ++ must see prior RCU read-side crit sects */
89 __get_cpu_var(dynticks_progress_counter)++;
90 WARN_ON(__get_cpu_var(dynticks_progress_counter) & 0x1);
93 static inline void rcu_exit_nohz(void)
95 __get_cpu_var(dynticks_progress_counter)++;
96 smp_mb(); /* CPUs seeing ++ must see later RCU read-side crit sects */
97 WARN_ON(!(__get_cpu_var(dynticks_progress_counter) & 0x1));
100 #else /* CONFIG_NO_HZ */
101 #define rcu_enter_nohz() do { } while (0)
102 #define rcu_exit_nohz() do { } while (0)
103 #endif /* CONFIG_NO_HZ */
105 #endif /* __LINUX_RCUPREEMPT_H */