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/* Spin locks.
Copyright (C) 2000-2020 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <sched.h>
/* The default for single processor machines; don't spin, it's
pointless. */
#ifndef __PTHREAD_SPIN_COUNT
# define __PTHREAD_SPIN_COUNT 1
#endif
/* The number of times to spin while trying to lock a spin lock object
before yielding the processor. */
int __pthread_spin_count = __PTHREAD_SPIN_COUNT;
/* Lock the spin lock object LOCK. If the lock is held by another
thread spin until it becomes available. */
int
_pthread_spin_lock (__pthread_spinlock_t *lock)
{
int i;
while (1)
{
for (i = 0; i < __pthread_spin_count; i++)
{
if (__pthread_spin_trylock (lock) == 0)
return 0;
}
__sched_yield ();
}
}
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