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-rw-r--r--libpthread/sysdeps/posix/pt-spin.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/libpthread/sysdeps/posix/pt-spin.c b/libpthread/sysdeps/posix/pt-spin.c
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+++ b/libpthread/sysdeps/posix/pt-spin.c
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+/* Spin locks.
+ Copyright (C) 2000, 2004 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 Library General Public License as
+ published by the Free Software Foundation; either version 2 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
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#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 ();
+ }
+}
+
+weak_alias (_pthread_spin_lock, pthread_spin_lock);
+weak_alias (_pthread_spin_lock, __pthread_spin_lock);