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8df13f0160
The cond_synchronize_rcu_expedited() API compresses the combined expedited and normal grace-period states into a single unsigned long, which conserves storage, but can miss grace periods in certain cases involving overlapping normal and expedited grace periods. Missing the occasional grace period is usually not a problem, but there are use cases that care about each and every grace period. This commit therefore adds yet another member of the full-state RCU grace-period polling API, which is the cond_synchronize_rcu_exp_full() function. This uses up to three times the storage (rcu_gp_oldstate structure instead of unsigned long), but is guaranteed not to miss grace periods. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Read-Copy Update mechanism for mutual exclusion (tree-based version)
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*
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* Copyright IBM Corporation, 2008
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*
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* Author: Dipankar Sarma <dipankar@in.ibm.com>
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* Paul E. McKenney <paulmck@linux.ibm.com> Hierarchical algorithm
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*
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* Based on the original work by Paul McKenney <paulmck@linux.ibm.com>
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* and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
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*
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* For detailed explanation of Read-Copy Update mechanism see -
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* Documentation/RCU
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*/
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#ifndef __LINUX_RCUTREE_H
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#define __LINUX_RCUTREE_H
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void rcu_softirq_qs(void);
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void rcu_note_context_switch(bool preempt);
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int rcu_needs_cpu(void);
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void rcu_cpu_stall_reset(void);
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/*
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* Note a virtualization-based context switch. This is simply a
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* wrapper around rcu_note_context_switch(), which allows TINY_RCU
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* to save a few bytes. The caller must have disabled interrupts.
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*/
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static inline void rcu_virt_note_context_switch(int cpu)
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{
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rcu_note_context_switch(false);
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}
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void synchronize_rcu_expedited(void);
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void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func);
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void rcu_barrier(void);
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bool rcu_eqs_special_set(int cpu);
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void rcu_momentary_dyntick_idle(void);
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void kfree_rcu_scheduler_running(void);
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bool rcu_gp_might_be_stalled(void);
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struct rcu_gp_oldstate {
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unsigned long rgos_norm;
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unsigned long rgos_exp;
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unsigned long rgos_polled;
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};
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unsigned long start_poll_synchronize_rcu_expedited(void);
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void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
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void cond_synchronize_rcu_expedited(unsigned long oldstate);
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void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp);
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unsigned long get_state_synchronize_rcu(void);
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void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
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unsigned long start_poll_synchronize_rcu(void);
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void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
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bool poll_state_synchronize_rcu(unsigned long oldstate);
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bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
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void cond_synchronize_rcu(unsigned long oldstate);
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void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp);
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bool rcu_is_idle_cpu(int cpu);
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#ifdef CONFIG_PROVE_RCU
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void rcu_irq_exit_check_preempt(void);
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#else
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static inline void rcu_irq_exit_check_preempt(void) { }
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#endif
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struct task_struct;
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void rcu_preempt_deferred_qs(struct task_struct *t);
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void exit_rcu(void);
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void rcu_scheduler_starting(void);
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extern int rcu_scheduler_active;
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void rcu_end_inkernel_boot(void);
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bool rcu_inkernel_boot_has_ended(void);
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bool rcu_is_watching(void);
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#ifndef CONFIG_PREEMPTION
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void rcu_all_qs(void);
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#endif
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/* RCUtree hotplug events */
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int rcutree_prepare_cpu(unsigned int cpu);
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int rcutree_online_cpu(unsigned int cpu);
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int rcutree_offline_cpu(unsigned int cpu);
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int rcutree_dead_cpu(unsigned int cpu);
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int rcutree_dying_cpu(unsigned int cpu);
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void rcu_cpu_starting(unsigned int cpu);
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#endif /* __LINUX_RCUTREE_H */
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