diff options
Diffstat (limited to 'lib/libthr/thread/thr_pspinlock.c')
| -rw-r--r-- | lib/libthr/thread/thr_pspinlock.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_pspinlock.c b/lib/libthr/thread/thr_pspinlock.c new file mode 100644 index 000000000000..4820490ab6af --- /dev/null +++ b/lib/libthr/thread/thr_pspinlock.c @@ -0,0 +1,153 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2003 David Xu <davidxu@freebsd.org> + * Copyright (c) 2016 The FreeBSD Foundation + * All rights reserved. + * + * Portions of this software were developed by Konstantin Belousov + * under sponsorship from the FreeBSD Foundation. + * + * 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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. + */ + +#include "namespace.h" +#include <errno.h> +#include <stdlib.h> +#include <pthread.h> +#include "un-namespace.h" + +#include "thr_private.h" + +_Static_assert(sizeof(struct pthread_spinlock) <= THR_PAGE_SIZE_MIN, + "pthread_spinlock is too large for off-page"); + +#define SPIN_COUNT 100000 + +__weak_reference(_pthread_spin_init, pthread_spin_init); +__weak_reference(_pthread_spin_destroy, pthread_spin_destroy); +__weak_reference(_pthread_spin_trylock, pthread_spin_trylock); +__weak_reference(_pthread_spin_lock, pthread_spin_lock); +__weak_reference(_pthread_spin_unlock, pthread_spin_unlock); + +int +_pthread_spin_init(pthread_spinlock_t *lock, int pshared) +{ + struct pthread_spinlock *lck; + + if (lock == NULL) + return (EINVAL); + if (pshared == PTHREAD_PROCESS_PRIVATE) { + lck = aligned_alloc(CACHE_LINE_SIZE, + roundup(sizeof(struct pthread_spinlock), CACHE_LINE_SIZE)); + if (lck == NULL) + return (ENOMEM); + *lock = lck; + } else if (pshared == PTHREAD_PROCESS_SHARED) { + lck = __thr_pshared_offpage(lock, 1); + if (lck == NULL) + return (EFAULT); + *lock = THR_PSHARED_PTR; + } else { + return (EINVAL); + } + _thr_umutex_init(&lck->s_lock); + return (0); +} + +int +_pthread_spin_destroy(pthread_spinlock_t *lock) +{ + void *l; + int ret; + + if (lock == NULL || *lock == NULL) { + ret = EINVAL; + } else if (*lock == THR_PSHARED_PTR) { + l = __thr_pshared_offpage(lock, 0); + if (l != NULL) + __thr_pshared_destroy(l); + ret = 0; + } else { + free(*lock); + *lock = NULL; + ret = 0; + } + return (ret); +} + +int +_pthread_spin_trylock(pthread_spinlock_t *lock) +{ + struct pthread_spinlock *lck; + + if (lock == NULL || *lock == NULL) + return (EINVAL); + lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; + if (lck == NULL) + return (EINVAL); + return (THR_UMUTEX_TRYLOCK(_get_curthread(), &lck->s_lock)); +} + +int +_pthread_spin_lock(pthread_spinlock_t *lock) +{ + struct pthread *curthread; + struct pthread_spinlock *lck; + int count; + + if (lock == NULL) + return (EINVAL); + lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; + if (lck == NULL) + return (EINVAL); + + curthread = _get_curthread(); + count = SPIN_COUNT; + while (THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock) != 0) { + while (lck->s_lock.m_owner) { + if (!_thr_is_smp) { + _pthread_yield(); + } else { + CPU_SPINWAIT; + if (--count <= 0) { + count = SPIN_COUNT; + _pthread_yield(); + } + } + } + } + return (0); +} + +int +_pthread_spin_unlock(pthread_spinlock_t *lock) +{ + struct pthread_spinlock *lck; + + if (lock == NULL) + return (EINVAL); + lck = *lock == THR_PSHARED_PTR ? __thr_pshared_offpage(lock, 0) : *lock; + if (lck == NULL) + return (EINVAL); + return (THR_UMUTEX_UNLOCK(_get_curthread(), &lck->s_lock)); +} |