diff options
Diffstat (limited to 'libpthread/sysdeps/posix/pt-spin.c')
-rw-r--r-- | libpthread/sysdeps/posix/pt-spin.c | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/libpthread/sysdeps/posix/pt-spin.c b/libpthread/sysdeps/posix/pt-spin.c new file mode 100644 index 00000000..486030de --- /dev/null +++ b/libpthread/sysdeps/posix/pt-spin.c @@ -0,0 +1,54 @@ +/* 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); |