diff options
Diffstat (limited to 'lib/libpthread/thread/thr_spinlock.c')
| -rw-r--r-- | lib/libpthread/thread/thr_spinlock.c | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/lib/libpthread/thread/thr_spinlock.c b/lib/libpthread/thread/thr_spinlock.c new file mode 100644 index 0000000..deaeb9b --- /dev/null +++ b/lib/libpthread/thread/thr_spinlock.c @@ -0,0 +1,144 @@ +/* + * Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by John Birrell. + * 4. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + * + */ + +#include <sys/types.h> +#include <machine/atomic.h> + +#include <libc_private.h> +#include "spinlock.h" +#include "thr_private.h" + +#define MAX_SPINLOCKS 5 + +struct spinlock_extra { + spinlock_t *owner; + pthread_mutex_t lock; +}; + +static void init_spinlock(spinlock_t *lck); + +static pthread_mutex_t spinlock_static_lock; +static struct spinlock_extra extra[MAX_SPINLOCKS]; +static int spinlock_count = 0; +static int initialized = 0; + +/* + * These are for compatability only. Spinlocks of this type + * are deprecated. + */ + +void +_spinunlock(spinlock_t *lck) +{ + struct spinlock_extra *extra; + + extra = (struct spinlock_extra *)lck->fname; + pthread_mutex_unlock(&extra->lock); +} + +/* + * Lock a location for the running thread. Yield to allow other + * threads to run if this thread is blocked because the lock is + * not available. Note that this function does not sleep. It + * assumes that the lock will be available very soon. + */ +void +_spinlock(spinlock_t *lck) +{ + struct spinlock_extra *extra; + + if (!__isthreaded) + PANIC("Spinlock called when not threaded."); + if (!initialized) + PANIC("Spinlocks not initialized."); + /* + * Try to grab the lock and loop if another thread grabs + * it before we do. + */ + if (lck->fname == NULL) + init_spinlock(lck); + extra = (struct spinlock_extra *)lck->fname; + pthread_mutex_lock(&extra->lock); +} + +/* + * Lock a location for the running thread. Yield to allow other + * threads to run if this thread is blocked because the lock is + * not available. Note that this function does not sleep. It + * assumes that the lock will be available very soon. + * + * This function checks if the running thread has already locked the + * location, warns if this occurs and creates a thread dump before + * returning. + */ +void +_spinlock_debug(spinlock_t *lck, char *fname, int lineno) +{ + _spinlock(lck); +} + +static void +init_spinlock(spinlock_t *lck) +{ + pthread_mutex_lock(&spinlock_static_lock); + if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) { + lck->fname = (char *)&extra[spinlock_count]; + extra[spinlock_count].owner = lck; + spinlock_count++; + } + pthread_mutex_unlock(&spinlock_static_lock); + if (lck->fname == NULL) + PANIC("Exceeded max spinlocks"); +} + +void +_thr_spinlock_init(void) +{ + int i; + + if (initialized != 0) { + _thr_mutex_reinit(&spinlock_static_lock); + for (i = 0; i < spinlock_count; i++) + _thr_mutex_reinit(&extra[i].lock); + } else { + if (pthread_mutex_init(&spinlock_static_lock, NULL)) + PANIC("Cannot initialize spinlock_static_lock"); + for (i = 0; i < MAX_SPINLOCKS; i++) { + if (pthread_mutex_init(&extra[i].lock, NULL)) + PANIC("Cannot initialize spinlock extra"); + } + initialized = 1; + } +} |
