2 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
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, you can access it online at
16 * http://www.gnu.org/licenses/gpl-2.0.html.
18 * Copyright IBM Corporation, 2008
20 * Author: Dipankar Sarma <dipankar@in.ibm.com>
21 * Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
23 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
24 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
26 * For detailed explanation of Read-Copy Update mechanism see -
30 #ifndef __LINUX_RCUTREE_H
31 #define __LINUX_RCUTREE_H
33 void rcu_note_context_switch(void);
34 int rcu_needs_cpu(u64 basem, u64 *nextevt);
35 void rcu_cpu_stall_reset(void);
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.
42 static inline void rcu_virt_note_context_switch(int cpu)
44 rcu_note_context_switch();
47 #ifdef CONFIG_PREEMPT_RT_FULL
48 # define synchronize_rcu_bh synchronize_rcu
50 void synchronize_rcu_bh(void);
52 void synchronize_sched_expedited(void);
53 void synchronize_rcu_expedited(void);
55 void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
58 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
60 * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
61 * approach to force the grace period to end quickly. This consumes
62 * significant time on all CPUs and is unfriendly to real-time workloads,
63 * so is thus not recommended for any sort of common-case code. In fact,
64 * if you are using synchronize_rcu_bh_expedited() in a loop, please
65 * restructure your code to batch your updates, and then use a single
66 * synchronize_rcu_bh() instead.
68 * Note that it is illegal to call this function while holding any lock
69 * that is acquired by a CPU-hotplug notifier. And yes, it is also illegal
70 * to call this function from a CPU-hotplug notifier. Failing to observe
71 * these restriction will result in deadlock.
73 static inline void synchronize_rcu_bh_expedited(void)
75 synchronize_sched_expedited();
78 void rcu_barrier(void);
79 #ifdef CONFIG_PREEMPT_RT_FULL
80 # define rcu_barrier_bh rcu_barrier
82 void rcu_barrier_bh(void);
84 void rcu_barrier_sched(void);
85 unsigned long get_state_synchronize_rcu(void);
86 void cond_synchronize_rcu(unsigned long oldstate);
87 unsigned long get_state_synchronize_sched(void);
88 void cond_synchronize_sched(unsigned long oldstate);
90 extern unsigned long rcutorture_testseq;
91 extern unsigned long rcutorture_vernum;
92 unsigned long rcu_batches_started(void);
93 unsigned long rcu_batches_started_bh(void);
94 unsigned long rcu_batches_started_sched(void);
95 unsigned long rcu_batches_completed(void);
96 unsigned long rcu_batches_completed_sched(void);
97 void show_rcu_gp_kthreads(void);
99 void rcu_force_quiescent_state(void);
100 void rcu_sched_force_quiescent_state(void);
102 void rcu_idle_enter(void);
103 void rcu_idle_exit(void);
104 void rcu_irq_enter(void);
105 void rcu_irq_exit(void);
109 void rcu_scheduler_starting(void);
110 extern int rcu_scheduler_active __read_mostly;
112 bool rcu_is_watching(void);
114 #ifndef CONFIG_PREEMPT_RT_FULL
115 void rcu_bh_force_quiescent_state(void);
116 unsigned long rcu_batches_completed_bh(void);
118 # define rcu_bh_force_quiescent_state rcu_force_quiescent_state
119 # define rcu_batches_completed_bh rcu_batches_completed
122 void rcu_all_qs(void);
124 #endif /* __LINUX_RCUTREE_H */