blob: 52953790dcca2089527ec9f48725fd7d31fb0da0 [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
Paul E. McKenney87de1cf2013-12-03 10:02:52 -080015 * along with this program; if not, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010017 *
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
Paul E. McKenney38200cf2014-10-21 12:50:04 -070033void rcu_note_context_switch(void);
Paul E. McKenneyffa83fb2013-11-17 19:27:16 -080034#ifndef CONFIG_RCU_NOCB_CPU_ALL
Paul E. McKenneyaa6da512014-10-21 13:23:08 -070035int rcu_needs_cpu(unsigned long *delta_jiffies);
Paul E. McKenneyffa83fb2013-11-17 19:27:16 -080036#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */
Teodora Baluta584dc4c2013-11-11 17:11:23 +020037void rcu_cpu_stall_reset(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010038
Gleb Natapov29ce8312011-05-04 16:31:03 +030039/*
40 * Note a virtualization-based context switch. This is simply a
41 * wrapper around rcu_note_context_switch(), which allows TINY_RCU
42 * to save a few bytes.
43 */
44static inline void rcu_virt_note_context_switch(int cpu)
45{
Paul E. McKenney38200cf2014-10-21 12:50:04 -070046 rcu_note_context_switch();
Gleb Natapov29ce8312011-05-04 16:31:03 +030047}
48
Teodora Baluta584dc4c2013-11-11 17:11:23 +020049void synchronize_rcu_bh(void);
50void synchronize_sched_expedited(void);
51void synchronize_rcu_expedited(void);
Paul E. McKenney03b042b2009-06-25 09:08:16 -070052
Paul E. McKenney486e2592012-01-06 14:11:30 -080053void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
54
Paul E. McKenney236fefa2012-01-31 14:00:41 -080055/**
56 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
57 *
58 * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
59 * approach to force the grace period to end quickly. This consumes
60 * significant time on all CPUs and is unfriendly to real-time workloads,
61 * so is thus not recommended for any sort of common-case code. In fact,
62 * if you are using synchronize_rcu_bh_expedited() in a loop, please
63 * restructure your code to batch your updates, and then use a single
64 * synchronize_rcu_bh() instead.
65 *
66 * Note that it is illegal to call this function while holding any lock
67 * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal
68 * to call this function from a CPU-hotplug notifier. Failing to observe
69 * these restriction will result in deadlock.
70 */
Paul E. McKenney03b042b2009-06-25 09:08:16 -070071static inline void synchronize_rcu_bh_expedited(void)
72{
73 synchronize_sched_expedited();
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010074}
75
Teodora Baluta584dc4c2013-11-11 17:11:23 +020076void rcu_barrier(void);
77void rcu_barrier_bh(void);
78void rcu_barrier_sched(void);
Paul E. McKenney765a3f42014-03-14 16:37:08 -070079unsigned long get_state_synchronize_rcu(void);
80void cond_synchronize_rcu(unsigned long oldstate);
Paul E. McKenneya57eb942010-06-29 16:49:16 -070081
Paul E. McKenney4a298652011-04-03 21:33:51 -070082extern unsigned long rcutorture_testseq;
83extern unsigned long rcutorture_vernum;
Teodora Baluta584dc4c2013-11-11 17:11:23 +020084long rcu_batches_completed(void);
85long rcu_batches_completed_bh(void);
86long rcu_batches_completed_sched(void);
Paul E. McKenneyafea2272014-03-12 07:10:41 -070087void show_rcu_gp_kthreads(void);
Paul E. McKenney4a298652011-04-03 21:33:51 -070088
Teodora Baluta584dc4c2013-11-11 17:11:23 +020089void rcu_force_quiescent_state(void);
90void rcu_bh_force_quiescent_state(void);
91void rcu_sched_force_quiescent_state(void);
Paul E. McKenney64db4cf2008-12-18 21:55:32 +010092
Teodora Baluta584dc4c2013-11-11 17:11:23 +020093void exit_rcu(void);
Paul E. McKenney2439b692013-04-11 10:15:52 -070094
Teodora Baluta584dc4c2013-11-11 17:11:23 +020095void rcu_scheduler_starting(void);
Paul E. McKenneybbad9372010-04-02 16:17:17 -070096extern int rcu_scheduler_active __read_mostly;
97
Teodora Baluta584dc4c2013-11-11 17:11:23 +020098bool rcu_is_watching(void);
Paul E. McKenneycc6783f2013-09-06 17:39:49 -070099
Paul E. McKenney64db4cf2008-12-18 21:55:32 +0100100#endif /* __LINUX_RCUTREE_H */