[deliverable/linux.git] / include / linux / rcutree.h

/*
 * Read-Copy Update mechanism for mutual exclusion (tree-based version)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you can access it online at
 * http://www.gnu.org/licenses/gpl-2.0.html.
 *
 * Copyright IBM Corporation, 2008
 *
 * Author: Dipankar Sarma <dipankar@in.ibm.com>
 *	   Paul E. McKenney <paulmck@linux.vnet.ibm.com> Hierarchical algorithm
 *
 * Based on the original work by Paul McKenney <paulmck@us.ibm.com>
 * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
 *
 * For detailed explanation of Read-Copy Update mechanism see -
 *	Documentation/RCU
 */

#ifndef __LINUX_RCUTREE_H
#define __LINUX_RCUTREE_H

void rcu_note_context_switch(void);
int rcu_needs_cpu(u64 basem, u64 *nextevt);
void rcu_cpu_stall_reset(void);

/*
 * Note a virtualization-based context switch.  This is simply a
 * wrapper around rcu_note_context_switch(), which allows TINY_RCU
 * to save a few bytes. The caller must have disabled interrupts.
 */
static inline void rcu_virt_note_context_switch(int cpu)
{
	rcu_note_context_switch();
}

void synchronize_rcu_bh(void);
void synchronize_sched_expedited(void);
void synchronize_rcu_expedited(void);

void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func);

/**
 * synchronize_rcu_bh_expedited - Brute-force RCU-bh grace period
 *
 * Wait for an RCU-bh grace period to elapse, but use a "big hammer"
 * approach to force the grace period to end quickly.  This consumes
 * significant time on all CPUs and is unfriendly to real-time workloads,
 * so is thus not recommended for any sort of common-case code.  In fact,
 * if you are using synchronize_rcu_bh_expedited() in a loop, please
 * restructure your code to batch your updates, and then use a single
 * synchronize_rcu_bh() instead.
 *
 * Note that it is illegal to call this function while holding any lock
 * that is acquired by a CPU-hotplug notifier.  And yes, it is also illegal
 * to call this function from a CPU-hotplug notifier.  Failing to observe
 * these restriction will result in deadlock.
 */
static inline void synchronize_rcu_bh_expedited(void)
{
	synchronize_sched_expedited();
}

void rcu_barrier(void);
void rcu_barrier_bh(void);
void rcu_barrier_sched(void);
unsigned long get_state_synchronize_rcu(void);
void cond_synchronize_rcu(unsigned long oldstate);
unsigned long get_state_synchronize_sched(void);
void cond_synchronize_sched(unsigned long oldstate);

extern unsigned long rcutorture_testseq;
extern unsigned long rcutorture_vernum;
unsigned long rcu_batches_started(void);
unsigned long rcu_batches_started_bh(void);
unsigned long rcu_batches_started_sched(void);
unsigned long rcu_batches_completed(void);
unsigned long rcu_batches_completed_bh(void);
unsigned long rcu_batches_completed_sched(void);
unsigned long rcu_exp_batches_completed(void);
unsigned long rcu_exp_batches_completed_sched(void);
void show_rcu_gp_kthreads(void);

void rcu_force_quiescent_state(void);
void rcu_bh_force_quiescent_state(void);
void rcu_sched_force_quiescent_state(void);

void rcu_idle_enter(void);
void rcu_idle_exit(void);
void rcu_irq_enter(void);
void rcu_irq_exit(void);
void rcu_irq_enter_irqson(void);
void rcu_irq_exit_irqson(void);

void exit_rcu(void);

void rcu_scheduler_starting(void);
extern int rcu_scheduler_active __read_mostly;

bool rcu_is_watching(void);

void rcu_all_qs(void);

/* RCUtree hotplug events */
int rcutree_prepare_cpu(unsigned int cpu);
int rcutree_online_cpu(unsigned int cpu);
int rcutree_offline_cpu(unsigned int cpu);
int rcutree_dead_cpu(unsigned int cpu);
int rcutree_dying_cpu(unsigned int cpu);

#endif /* __LINUX_RCUTREE_H */
Commit	Line	Data
	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
	33	void rcu_note_context_switch(void);
	34	int rcu_needs_cpu(u64 basem, u64 *nextevt);
	35	void 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	*/
	42	static inline void rcu_virt_note_context_switch(int cpu)
	43	{
	44	rcu_note_context_switch();
	45	}
	46
	47	void synchronize_rcu_bh(void);
	48	void synchronize_sched_expedited(void);
	49	void synchronize_rcu_expedited(void);
	50
	51	void 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	*/
	69	static inline void synchronize_rcu_bh_expedited(void)
	70	{
	71	synchronize_sched_expedited();
	72	}
	73
	74	void rcu_barrier(void);
	75	void rcu_barrier_bh(void);
	76	void rcu_barrier_sched(void);
	77	unsigned long get_state_synchronize_rcu(void);
	78	void cond_synchronize_rcu(unsigned long oldstate);
	79	unsigned long get_state_synchronize_sched(void);
	80	void cond_synchronize_sched(unsigned long oldstate);
	81
	82	extern unsigned long rcutorture_testseq;
	83	extern unsigned long rcutorture_vernum;
	84	unsigned long rcu_batches_started(void);
	85	unsigned long rcu_batches_started_bh(void);
	86	unsigned long rcu_batches_started_sched(void);
	87	unsigned long rcu_batches_completed(void);
	88	unsigned long rcu_batches_completed_bh(void);
	89	unsigned long rcu_batches_completed_sched(void);
	90	unsigned long rcu_exp_batches_completed(void);
	91	unsigned long rcu_exp_batches_completed_sched(void);
	92	void show_rcu_gp_kthreads(void);
	93
	94	void rcu_force_quiescent_state(void);
	95	void rcu_bh_force_quiescent_state(void);
	96	void rcu_sched_force_quiescent_state(void);
	97
	98	void rcu_idle_enter(void);
	99	void rcu_idle_exit(void);
	100	void rcu_irq_enter(void);
	101	void rcu_irq_exit(void);
	102	void rcu_irq_enter_irqson(void);
	103	void rcu_irq_exit_irqson(void);
	104
	105	void exit_rcu(void);
	106
	107	void rcu_scheduler_starting(void);
	108	extern int rcu_scheduler_active __read_mostly;
	109
	110	bool rcu_is_watching(void);
	111
	112	void rcu_all_qs(void);
	113
	114	/* RCUtree hotplug events */
	115	int rcutree_prepare_cpu(unsigned int cpu);
	116	int rcutree_online_cpu(unsigned int cpu);
	117	int rcutree_offline_cpu(unsigned int cpu);
	118	int rcutree_dead_cpu(unsigned int cpu);
	119	int rcutree_dying_cpu(unsigned int cpu);
	120
	121	#endif /* __LINUX_RCUTREE_H */