include/linux/rcutree.h

   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(bool preempt);
  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(false);
  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 void rcu_idle_enter(void);
  83 void rcu_idle_exit(void);
  84 void rcu_irq_enter(void);
  85 void rcu_irq_exit(void);
  86 void rcu_irq_enter_irqson(void);
  87 void rcu_irq_exit_irqson(void);
  88 bool rcu_irq_enter_disabled(void);
  89
  90 void exit_rcu(void);
  91
  92 void rcu_scheduler_starting(void);
  93 extern int rcu_scheduler_active __read_mostly;
  94 void rcu_end_inkernel_boot(void);
  95 bool rcu_is_watching(void);
  96 void rcu_all_qs(void);
  97
  98 /* RCUtree hotplug events */
  99 int rcutree_prepare_cpu(unsigned int cpu);
 100 int rcutree_online_cpu(unsigned int cpu);
 101 int rcutree_offline_cpu(unsigned int cpu);
 102 int rcutree_dead_cpu(unsigned int cpu);
 103 int rcutree_dying_cpu(unsigned int cpu);
 104
 105 #endif /* __LINUX_RCUTREE_H */