tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Read-Copy Update mechanism for mutual exclusion (RT implementation)
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 (C) IBM Corporation, 2006
19 *
20 * Author: Paul McKenney <paulmck@us.ibm.com>
21 *
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)
27 *
28 * For detailed explanation of Read-Copy Update mechanism see -
29 * Documentation/RCU
30 *
31 */
32
33#ifndef __LINUX_RCUPREEMPT_H
34#define __LINUX_RCUPREEMPT_H
35
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>
42
43#define rcu_qsctr_inc(cpu)
44#define rcu_bh_qsctr_inc(cpu)
45#define call_rcu_bh(head, rcu) call_rcu(head, rcu)
46
47extern void __rcu_read_lock(void) __acquires(RCU);
48extern void __rcu_read_unlock(void) __releases(RCU);
49extern int rcu_pending(int cpu);
50extern int rcu_needs_cpu(int cpu);
51
52#define __rcu_read_lock_bh() { rcu_read_lock(); local_bh_disable(); }
53#define __rcu_read_unlock_bh() { local_bh_enable(); rcu_read_unlock(); }
54
55extern void __synchronize_sched(void);
56
57extern void __rcu_init(void);
58extern void rcu_check_callbacks(int cpu, int user);
59extern void rcu_restart_cpu(int cpu);
60extern long rcu_batches_completed(void);
61
62/*
63 * Return the number of RCU batches processed thus far. Useful for debug
64 * and statistic. The _bh variant is identifcal to straight RCU
65 */
66static inline long rcu_batches_completed_bh(void)
67{
68 return rcu_batches_completed();
69}
70
71#ifdef CONFIG_RCU_TRACE
72struct rcupreempt_trace;
73extern long *rcupreempt_flipctr(int cpu);
74extern long rcupreempt_data_completed(void);
75extern int rcupreempt_flip_flag(int cpu);
76extern int rcupreempt_mb_flag(int cpu);
77extern char *rcupreempt_try_flip_state_name(void);
78extern struct rcupreempt_trace *rcupreempt_trace_cpu(int cpu);
79#endif
80
81struct softirq_action;
82
83#ifdef CONFIG_NO_HZ
84DECLARE_PER_CPU(long, dynticks_progress_counter);
85
86static inline void rcu_enter_nohz(void)
87{
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);
91}
92
93static inline void rcu_exit_nohz(void)
94{
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));
98}
99
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 */
104
105#endif /* __LINUX_RCUPREEMPT_H */