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Implement process-shared spinlocks.

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Sponsored by:	The FreeBSD Foundation
This commit is contained in:
Konstantin Belousov 2016-03-21 06:40:54 +00:00
parent e13c604596
commit 6eced731e8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=297138
1 changed files with 58 additions and 47 deletions
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105
lib/libthr/thread/thr_pspinlock.c
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@ -1,7 +1,11 @@
/*-
* 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:
@ -46,93 +50,100 @@ int
_pthread_spin_init(pthread_spinlock_t *lock, int pshared)
{
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || pshared != PTHREAD_PROCESS_PRIVATE)
ret = EINVAL;
else if ((lck = malloc(sizeof(struct pthread_spinlock))) == NULL)
ret = ENOMEM;
else {
_thr_umutex_init(&lck->s_lock);
if (lock == NULL)
return (EINVAL);
if (pshared == PTHREAD_PROCESS_PRIVATE) {
lck = malloc(sizeof(struct pthread_spinlock));
if (lck == NULL)
return (ENOMEM);
*lock = lck;
ret = 0;
} else if (pshared == PTHREAD_PROCESS_SHARED) {
lck = __thr_pshared_offpage(lock, 1);
if (lck == NULL)
return (EFAULT);
*lock = THR_PSHARED_PTR;
} else {
return (EINVAL);
}
return (ret);
_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)
if (lock == NULL || *lock == NULL) {
ret = EINVAL;
else {
} 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 *curthread = _get_curthread();
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else
ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock);
return (ret);
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 = _get_curthread();
struct pthread *curthread;
struct pthread_spinlock *lck;
int ret, count;
int count;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else {
count = SPIN_COUNT;
while ((ret = THR_UMUTEX_TRYLOCK(curthread, &lck->s_lock)) != 0) {
while (lck->s_lock.m_owner) {
if (!_thr_is_smp) {
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();
} else {
CPU_SPINWAIT;
if (--count <= 0) {
count = SPIN_COUNT;
_pthread_yield();
}
}
}
}
ret = 0;
}
return (ret);
return (0);
}
int
_pthread_spin_unlock(pthread_spinlock_t *lock)
{
struct pthread *curthread = _get_curthread();
struct pthread_spinlock *lck;
int ret;
if (lock == NULL || (lck = *lock) == NULL)
ret = EINVAL;
else {
ret = THR_UMUTEX_UNLOCK(curthread, &lck->s_lock);
}
return (ret);
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));
}