1/* 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, you can access it online at 16 * http://www.gnu.org/licenses/gpl-2.0.html. 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 - 27 * Documentation/RCU 28 */ 29 30#ifndef __LINUX_RCUTREE_H 31#define __LINUX_RCUTREE_H 32 33void rcu_note_context_switch(void); 34int rcu_needs_cpu(u64 basem, u64 *nextevt); 35void rcu_cpu_stall_reset(void); 36 37/* 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. The caller must have disabled interrupts. 41 */ 42static inline void rcu_virt_note_context_switch(int cpu) 43{ 44 rcu_note_context_switch(); 45} 46 47void synchronize_rcu_bh(void); 48void synchronize_sched_expedited(void); 49void synchronize_rcu_expedited(void); 50 51void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func); 52 53/** 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 */ 69static inline void synchronize_rcu_bh_expedited(void) 70{ 71 synchronize_sched_expedited(); 72} 73 74void rcu_barrier(void); 75void rcu_barrier_bh(void); 76void rcu_barrier_sched(void); 77unsigned long get_state_synchronize_rcu(void); 78void cond_synchronize_rcu(unsigned long oldstate); 79unsigned long get_state_synchronize_sched(void); 80void cond_synchronize_sched(unsigned long oldstate); 81 82extern unsigned long rcutorture_testseq; 83extern unsigned long rcutorture_vernum; 84unsigned long rcu_batches_started(void); 85unsigned long rcu_batches_started_bh(void); 86unsigned long rcu_batches_started_sched(void); 87unsigned long rcu_batches_completed(void); 88unsigned long rcu_batches_completed_bh(void); 89unsigned long rcu_batches_completed_sched(void); 90void show_rcu_gp_kthreads(void); 91 92void rcu_force_quiescent_state(void); 93void rcu_bh_force_quiescent_state(void); 94void rcu_sched_force_quiescent_state(void); 95 96void rcu_idle_enter(void); 97void rcu_idle_exit(void); 98void rcu_irq_enter(void); 99void rcu_irq_exit(void); 100void rcu_irq_enter_irqson(void); 101void rcu_irq_exit_irqson(void); 102 103void exit_rcu(void); 104 105void rcu_scheduler_starting(void); 106extern int rcu_scheduler_active __read_mostly; 107 108bool rcu_is_watching(void); 109 110void rcu_all_qs(void); 111 112#endif /* __LINUX_RCUTREE_H */ 113