blob: 72137ee8c603b2c0c45ea7f729211e12cfad3941 [file] [log] [blame]
Paul E. McKenney64db4cf2008-12-18 21:55:32 +01001/*
2 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
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: Dipankar Sarma <dipankar@in.ibm.com>
21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
22 *
23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
25 *
26 * For detailed explanation of Read-Copy Update mechanism see -
Paul E. McKenneya71fca52009-09-18 10:28:19 -070027 * Documentation/RCU
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010028 */
29
30#ifndef __LINUX_RCUTREE_H
31#define __LINUX_RCUTREE_H
32
Teodora Baluta584dc4c2013-11-11 17:11:23 +020033void rcu_note_context_switch(int cpu);
34int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);
35void rcu_cpu_stall_reset(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010036
Gleb Natapov29ce8312011-05-04 16:31:03 +030037/*
38 * Note a virtualization-based context switch. This is simply a
39 * wrapper around rcu_note_context_switch(), which allows TINY_RCU
40 * to save a few bytes.
41 */
42static inline void rcu_virt_note_context_switch(int cpu)
43{
44 rcu_note_context_switch(cpu);
45}
46
Teodora Baluta584dc4c2013-11-11 17:11:23 +020047void synchronize_rcu_bh(void);
48void synchronize_sched_expedited(void);
49void synchronize_rcu_expedited(void);
Paul E. McKenney03b042b2009-06-25 09:08:16 -070050
Paul E. McKenney486e2592012-01-06 14:11:30 -080051void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
52
Paul E. McKenney236fefa2012-01-31 14:00:41 -080053/**
54 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
55 *
56 * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
57 * approach to force the grace period to end quickly. This consumes
58 * significant time on all CPUs and is unfriendly to real-time workloads,
59 * so is thus not recommended for any sort of common-case code. In fact,
60 * if you are using synchronize_rcu_bh_expedited() in a loop, please
61 * restructure your code to batch your updates, and then use a single
62 * synchronize_rcu_bh() instead.
63 *
64 * Note that it is illegal to call this function while holding any lock
65 * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal
66 * to call this function from a CPU-hotplug notifier. Failing to observe
67 * these restriction will result in deadlock.
68 */
Paul E. McKenney03b042b2009-06-25 09:08:16 -070069static inline void synchronize_rcu_bh_expedited(void)
70{
71 synchronize_sched_expedited();
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010072}
73
Teodora Baluta584dc4c2013-11-11 17:11:23 +020074void rcu_barrier(void);
75void rcu_barrier_bh(void);
76void rcu_barrier_sched(void);
Paul E. McKenneya57eb942010-06-29 16:49:16 -070077
Paul E. McKenney4a298652011-04-03 21:33:51 -070078extern unsigned long rcutorture_testseq;
79extern unsigned long rcutorture_vernum;
Teodora Baluta584dc4c2013-11-11 17:11:23 +020080long rcu_batches_completed(void);
81long rcu_batches_completed_bh(void);
82long rcu_batches_completed_sched(void);
Paul E. McKenney4a298652011-04-03 21:33:51 -070083
Teodora Baluta584dc4c2013-11-11 17:11:23 +020084void rcu_force_quiescent_state(void);
85void rcu_bh_force_quiescent_state(void);
86void rcu_sched_force_quiescent_state(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010087
Teodora Baluta584dc4c2013-11-11 17:11:23 +020088void exit_rcu(void);
Paul E. McKenney2439b692013-04-11 10:15:52 -070089
Teodora Baluta584dc4c2013-11-11 17:11:23 +020090void rcu_scheduler_starting(void);
Paul E. McKenneybbad9372010-04-02 16:17:17 -070091extern int rcu_scheduler_active __read_mostly;
92
Teodora Baluta584dc4c2013-11-11 17:11:23 +020093bool rcu_is_watching(void);
Paul E. McKenneycc6783f2013-09-06 17:39:49 -070094
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010095#endif /* __LINUX_RCUTREE_H */