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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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40
libc/intrin/pthread_mutex_lock.c
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@ -16,12 +16,14 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/errno.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/futex.internal.h"
#include "libc/intrin/likely.h"
#include "libc/intrin/weaken.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
#include "third_party/nsync/mu.h"
/**
* Locks mutex.
@ -60,28 +62,18 @@
int pthread_mutex_lock(pthread_mutex_t *mutex) {
int c, d, t;
if (mutex->type == PTHREAD_MUTEX_NORMAL) {
// From Futexes Are Tricky Version 1.1 § Mutex, Take 3;
// Ulrich Drepper, Red Hat Incorporated, June 27, 2004.
c = 0;
if (!atomic_compare_exchange_strong_explicit(
&mutex->lock, &c, 1, memory_order_acquire, memory_order_relaxed)) {
if (c != 2) {
c = atomic_exchange_explicit(&mutex->lock, 2, memory_order_acquire);
}
while (c) {
_futex_wait(&mutex->lock, 2, mutex->pshared, 0);
c = atomic_exchange_explicit(&mutex->lock, 2, memory_order_acquire);
}
}
if (LIKELY(__tls_enabled && //
mutex->_type == PTHREAD_MUTEX_NORMAL && //
mutex->_pshared == PTHREAD_PROCESS_PRIVATE && //
weaken(nsync_mu_lock))) {
weaken(nsync_mu_lock)((nsync_mu *)mutex);
return 0;
}
t = gettid();
if (mutex->type == PTHREAD_MUTEX_ERRORCHECK) {
c = atomic_load_explicit(&mutex->lock, memory_order_relaxed);
if (mutex->_type == PTHREAD_MUTEX_ERRORCHECK) {
c = atomic_load_explicit(&mutex->_lock, memory_order_relaxed);
if ((c & 0x000fffff) == t) {
assert(!"deadlock");
return EDEADLK;
}
}
@ -90,29 +82,29 @@ int pthread_mutex_lock(pthread_mutex_t *mutex) {
c = 0;
d = 0x10100000 | t;
if (atomic_compare_exchange_weak_explicit(
&mutex->lock, &c, d, memory_order_acquire, memory_order_relaxed)) {
&mutex->_lock, &c, d, memory_order_acquire, memory_order_relaxed)) {
break;
} else {
if ((c & 0x000fffff) == t) {
if ((c & 0x0ff00000) < 0x0ff00000) {
c = atomic_fetch_add_explicit(&mutex->lock, 0x00100000,
c = atomic_fetch_add_explicit(&mutex->_lock, 0x00100000,
memory_order_relaxed);
break;
} else {
assert(!"recurse");
return EAGAIN;
}
}
if ((c & 0xf0000000) == 0x10000000) {
d = 0x20000000 | c;
if (atomic_compare_exchange_weak_explicit(&mutex->lock, &c, d,
if (atomic_compare_exchange_weak_explicit(&mutex->_lock, &c, d,
memory_order_acquire,
memory_order_relaxed)) {
c = d;
}
}
if ((c & 0xf0000000) == 0x20000000) {
_futex_wait(&mutex->lock, c, mutex->pshared, 0);
// _futex_wait(&mutex->_lock, c, mutex->_pshared, 0);
pthread_yield();
}
}
}