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120 lines
3.1 KiB
C
120 lines
3.1 KiB
C
/* Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <errno.h>
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#include "pthreadP.h"
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#include <lowlevellock.h>
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#ifndef LLL_MUTEX_LOCK
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# define LLL_MUTEX_LOCK(mutex) lll_mutex_lock (mutex)
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# define LLL_MUTEX_TRYLOCK(mutex) lll_mutex_trylock (mutex)
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#endif
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int
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__pthread_mutex_lock (mutex)
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pthread_mutex_t *mutex;
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{
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assert (sizeof (mutex->__size) >= sizeof (mutex->__data));
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pid_t id = THREAD_GETMEM (THREAD_SELF, tid);
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switch (__builtin_expect (mutex->__data.__kind, PTHREAD_MUTEX_TIMED_NP))
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{
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/* Recursive mutex. */
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case PTHREAD_MUTEX_RECURSIVE_NP:
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/* Check whether we already hold the mutex. */
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if (mutex->__data.__owner == id)
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{
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/* Just bump the counter. */
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if (__builtin_expect (mutex->__data.__count + 1 == 0, 0))
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/* Overflow of the counter. */
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return EAGAIN;
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++mutex->__data.__count;
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return 0;
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}
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/* We have to get the mutex. */
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LLL_MUTEX_LOCK (mutex->__data.__lock);
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mutex->__data.__count = 1;
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break;
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/* Error checking mutex. */
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case PTHREAD_MUTEX_ERRORCHECK_NP:
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/* Check whether we already hold the mutex. */
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if (mutex->__data.__owner == id)
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return EDEADLK;
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/* FALLTHROUGH */
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default:
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/* Correct code cannot set any other type. */
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case PTHREAD_MUTEX_TIMED_NP:
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simple:
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/* Normal mutex. */
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LLL_MUTEX_LOCK (mutex->__data.__lock);
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break;
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case PTHREAD_MUTEX_ADAPTIVE_NP:
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if (! __is_smp)
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goto simple;
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if (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0)
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{
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int cnt = 0;
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int max_cnt = MIN (MAX_ADAPTIVE_COUNT,
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mutex->__data.__spins * 2 + 10);
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do
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{
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if (cnt++ >= max_cnt)
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{
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LLL_MUTEX_LOCK (mutex->__data.__lock);
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break;
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}
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#ifdef BUSY_WAIT_NOP
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BUSY_WAIT_NOP;
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#endif
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}
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while (LLL_MUTEX_TRYLOCK (mutex->__data.__lock) != 0);
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mutex->__data.__spins += (cnt - mutex->__data.__spins) / 8;
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}
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break;
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}
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/* Record the ownership. */
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assert (mutex->__data.__owner == 0);
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mutex->__data.__owner = id;
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#ifndef NO_INCR
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++mutex->__data.__nusers;
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#endif
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return 0;
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}
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#ifndef __pthread_mutex_lock
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strong_alias (__pthread_mutex_lock, pthread_mutex_lock)
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strong_alias (__pthread_mutex_lock, __pthread_mutex_lock_internal)
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#endif
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