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04277e02d7
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51 lines
1.5 KiB
C
51 lines
1.5 KiB
C
/* Spin locks.
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Copyright (C) 2000-2019 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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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, see
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<http://www.gnu.org/licenses/>. */
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#include <pthread.h>
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#include <sched.h>
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/* The default for single processor machines; don't spin, it's
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pointless. */
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#ifndef __PTHREAD_SPIN_COUNT
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# define __PTHREAD_SPIN_COUNT 1
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#endif
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/* The number of times to spin while trying to lock a spin lock object
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before yielding the processor. */
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int __pthread_spin_count = __PTHREAD_SPIN_COUNT;
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/* Lock the spin lock object LOCK. If the lock is held by another
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thread spin until it becomes available. */
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int
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_pthread_spin_lock (__pthread_spinlock_t *lock)
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{
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int i;
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while (1)
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{
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for (i = 0; i < __pthread_spin_count; i++)
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{
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if (__pthread_spin_trylock (lock) == 0)
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return 0;
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}
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__sched_yield ();
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}
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}
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