https://github.com/torvalds/linux
Tip revision: 6995e2de6891c724bfeb2db33d7b87775f913ad1 authored by Linus Torvalds on 25 June 2023, 23:29:58 UTC
Linux 6.4
Linux 6.4
Tip revision: 6995e2d
rcutree.h
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Read-Copy Update mechanism for mutual exclusion (tree-based version)
*
* Copyright IBM Corporation, 2008
*
* Author: Dipankar Sarma <dipankar@in.ibm.com>
* Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical algorithm
*
* Based on the original work by Paul McKenney <paulmck@linux.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_softirq_qs(void);
void rcu_note_context_switch(bool preempt);
int rcu_needs_cpu(void);
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(void)
{
rcu_note_context_switch(false);
}
void synchronize_rcu_expedited(void);
void kvfree_call_rcu(struct rcu_head *head, void *ptr);
void rcu_barrier(void);
bool rcu_eqs_special_set(int cpu);
void rcu_momentary_dyntick_idle(void);
void kfree_rcu_scheduler_running(void);
bool rcu_gp_might_be_stalled(void);
struct rcu_gp_oldstate {
unsigned long rgos_norm;
unsigned long rgos_exp;
};
// Maximum number of rcu_gp_oldstate values corresponding to
// not-yet-completed RCU grace periods.
#define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 4
/**
* same_state_synchronize_rcu_full - Are two old-state values identical?
* @rgosp1: First old-state value.
* @rgosp2: Second old-state value.
*
* The two old-state values must have been obtained from either
* get_state_synchronize_rcu_full(), start_poll_synchronize_rcu_full(),
* or get_completed_synchronize_rcu_full(). Returns @true if the two
* values are identical and @false otherwise. This allows structures
* whose lifetimes are tracked by old-state values to push these values
* to a list header, allowing those structures to be slightly smaller.
*
* Note that equality is judged on a bitwise basis, so that an
* @rcu_gp_oldstate structure with an already-completed state in one field
* will compare not-equal to a structure with an already-completed state
* in the other field. After all, the @rcu_gp_oldstate structure is opaque
* so how did such a situation come to pass in the first place?
*/
static inline bool same_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp1,
struct rcu_gp_oldstate *rgosp2)
{
return rgosp1->rgos_norm == rgosp2->rgos_norm && rgosp1->rgos_exp == rgosp2->rgos_exp;
}
unsigned long start_poll_synchronize_rcu_expedited(void);
void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
void cond_synchronize_rcu_expedited(unsigned long oldstate);
void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
unsigned long get_state_synchronize_rcu(void);
void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
unsigned long start_poll_synchronize_rcu(void);
void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
bool poll_state_synchronize_rcu(unsigned long oldstate);
bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
void cond_synchronize_rcu(unsigned long oldstate);
void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
#ifdef CONFIG_PROVE_RCU
void rcu_irq_exit_check_preempt(void);
#else
static inline void rcu_irq_exit_check_preempt(void) { }
#endif
struct task_struct;
void rcu_preempt_deferred_qs(struct task_struct *t);
void exit_rcu(void);
void rcu_scheduler_starting(void);
extern int rcu_scheduler_active;
void rcu_end_inkernel_boot(void);
bool rcu_inkernel_boot_has_ended(void);
bool rcu_is_watching(void);
#ifndef CONFIG_PREEMPTION
void rcu_all_qs(void);
#endif
/* 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);
void rcu_cpu_starting(unsigned int cpu);
#endif /* __LINUX_RCUTREE_H */