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Use *NSYNC for POSIX threads locking APIs

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Condition variables, barriers, and r/w locks now work very well.
This commit is contained in:
Justine Tunney 2022-09-11 11:02:07 -07:00
parent 3de35e196c
commit b5cb71ab84
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GPG key ID: BE714B4575D6E328
197 changed files with 3734 additions and 3817 deletions
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33
libc/thread/pthread_rwlock_unlock.c
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@ -16,12 +16,8 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/futex.internal.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/mu.h"
/**
* Unlocks read-write lock.
@ -30,26 +26,11 @@
* @raise EINVAL if lock is in a bad state
*/
int pthread_rwlock_unlock(pthread_rwlock_t *rwlock) {
int old, waits;
for (;;) {
old = atomic_load_explicit(&rwlock->lock, memory_order_relaxed);
if (!old || old < -1) {
assert(!"badlock");
return EINVAL;
} else if (old == -1 || old == 1) {
waits = atomic_load_explicit(&rwlock->waits, memory_order_relaxed);
if (atomic_compare_exchange_weak_explicit(&rwlock->lock, &old, 0,
memory_order_acquire,
memory_order_relaxed)) {
if (waits && (IsLinux() || IsOpenbsd())) {
_futex_wake(&rwlock->lock, 1, rwlock->pshared);
}
return 0;
}
} else if (atomic_compare_exchange_weak_explicit(
&rwlock->lock, &old, old - 1, memory_order_acquire,
memory_order_relaxed)) {
return 0;
}
if (rwlock->_iswrite) {
rwlock->_iswrite = 0;
nsync_mu_unlock((nsync_mu *)rwlock);
} else {
nsync_mu_runlock((nsync_mu *)rwlock);
}
return 0;
}