The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/sys/turnstile.h

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*-
    2  * Copyright (c) 2002 John Baldwin <jhb@FreeBSD.org>
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  *
   14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   24  * SUCH DAMAGE.
   25  *
   26  * $FreeBSD: releng/10.1/sys/sys/turnstile.h 262192 2014-02-18 20:27:17Z jhb $
   27  */
   28 
   29 #ifndef _SYS_TURNSTILE_H_
   30 #define _SYS_TURNSTILE_H_
   31 
   32 /*
   33  * Turnstile interface.  Non-sleepable locks use a turnstile for the
   34  * queue of threads blocked on them when they are contested.  Each
   35  * turnstile contains two sub-queues: one for threads waiting for a
   36  * shared, or eread, lock, and one for threads waiting for an
   37  * exclusive, or write, lock.
   38  *
   39  * A thread calls turnstile_chain_lock() to lock the turnstile chain
   40  * associated with a given lock.  A thread calls turnstile_wait() when
   41  * the lock is contested to be put on the queue and block.  If a thread
   42  * calls turnstile_trywait() and decides to retry a lock operation instead
   43  * of blocking, it should call turnstile_cancel() to unlock the associated
   44  * turnstile chain lock.
   45  *
   46  * When a lock is released, the thread calls turnstile_lookup() to look
   47  * up the turnstile associated with the given lock in the hash table.  Then
   48  * it calls either turnstile_signal() or turnstile_broadcast() to mark
   49  * blocked threads for a pending wakeup.  turnstile_signal() marks the
   50  * highest priority blocked thread while turnstile_broadcast() marks all
   51  * blocked threads.  The turnstile_signal() function returns true if the
   52  * turnstile became empty as a result.  After the higher level code finishes
   53  * releasing the lock, turnstile_unpend() must be called to wake up the
   54  * pending thread(s) and give up ownership of the turnstile.
   55  *
   56  * Alternatively, if a thread wishes to relinquish ownership of a lock
   57  * without waking up any waiters, it may call turnstile_disown().
   58  *
   59  * When a lock is acquired that already has at least one thread contested
   60  * on it, the new owner of the lock must claim ownership of the turnstile
   61  * via turnstile_claim().
   62  *
   63  * Each thread allocates a turnstile at thread creation via turnstile_alloc()
   64  * and releases it at thread destruction via turnstile_free().  Note that
   65  * a turnstile is not tied to a specific thread and that the turnstile
   66  * released at thread destruction may not be the same turnstile that the
   67  * thread allocated when it was created.
   68  *
   69  * The highest priority thread blocked on a specified queue of a
   70  * turnstile can be obtained via turnstile_head().  A given queue can
   71  * also be queried to see if it is empty via turnstile_empty().
   72  */
   73 
   74 struct lock_object;
   75 struct thread;
   76 struct turnstile;
   77 
   78 #ifdef _KERNEL
   79 
   80 /* Which queue to block on or which queue to wakeup one or more threads from. */
   81 #define TS_EXCLUSIVE_QUEUE      0
   82 #define TS_SHARED_QUEUE         1
   83 
   84 /* The type of lock currently held. */
   85 #define TS_EXCLUSIVE_LOCK       TS_EXCLUSIVE_QUEUE
   86 #define TS_SHARED_LOCK          TS_SHARED_QUEUE
   87 
   88 void    init_turnstiles(void);
   89 void    turnstile_adjust(struct thread *, u_char);
   90 struct turnstile *turnstile_alloc(void);
   91 void    turnstile_broadcast(struct turnstile *, int);
   92 void    turnstile_cancel(struct turnstile *);
   93 void    turnstile_chain_lock(struct lock_object *);
   94 void    turnstile_chain_unlock(struct lock_object *);
   95 void    turnstile_claim(struct turnstile *);
   96 void    turnstile_disown(struct turnstile *);
   97 int     turnstile_empty(struct turnstile *ts, int queue);
   98 void    turnstile_free(struct turnstile *);
   99 struct thread *turnstile_head(struct turnstile *, int);
  100 struct turnstile *turnstile_lookup(struct lock_object *);
  101 int     turnstile_signal(struct turnstile *, int);
  102 struct turnstile *turnstile_trywait(struct lock_object *);
  103 void    turnstile_unpend(struct turnstile *, int);
  104 void    turnstile_wait(struct turnstile *, struct thread *, int);
  105 
  106 #endif  /* _KERNEL */
  107 #endif  /* _SYS_TURNSTILE_H_ */

Cache object: ba68debb77f87bef76d1dbd0229fd35a


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.