File: /Users/paulross/dev/linux/linux-3.13/include/linux/rcutree.h

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       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, write to the Free Software
      16:  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
      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: extern void rcu_note_context_switch(int cpu);
      34: extern int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);
      35: extern 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.
      41:  */
      42: static inline void rcu_virt_note_context_switch(int cpu)
      43: {
      44:     rcu_note_context_switch(cpu);
      45: }
      46: 
      47: extern void synchronize_rcu_bh(void);
      48: extern void synchronize_sched_expedited(void);
      49: extern void synchronize_rcu_expedited(void);
      50: 
      51: void kfree_call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
      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: extern void rcu_barrier(void);
      75: extern void rcu_barrier_bh(void);
      76: extern void rcu_barrier_sched(void);
      77: 
      78: extern unsigned long rcutorture_testseq;
      79: extern unsigned long rcutorture_vernum;
      80: extern long rcu_batches_completed(void);
      81: extern long rcu_batches_completed_bh(void);
      82: extern long rcu_batches_completed_sched(void);
      83: 
      84: extern void rcu_force_quiescent_state(void);
      85: extern void rcu_bh_force_quiescent_state(void);
      86: extern void rcu_sched_force_quiescent_state(void);
      87: 
      88: extern void exit_rcu(void);
      89: 
      90: extern void rcu_scheduler_starting(void);
      91: extern int rcu_scheduler_active __read_mostly;
      92: 
      93: extern bool rcu_is_watching(void);
      94: 
      95: #endif /* __LINUX_RCUTREE_H */
      96: