/*
* Allocate new node
* If freeNodes list empty and # nodes < maxNodes, allocate new node
*/
stpcNode* _newNode(stpcProxy* proxy, bool alloc) {
stpcNode* node = NULL;
sequencedPtr oldFree, newFree;
oldFree.ival = atomic_load_explicit(&proxy->freeHead.ival, memory_order_acquire);
while (oldFree.ptr != atomic_load_explicit(&proxy->freeTail, memory_order_relaxed)) {
newFree.ptr = oldFree.ptr->next;
newFree.sequence = oldFree.sequence + 1;
if (atomic_compare_exchange_strong_explicit(&proxy->freeHead.ival, &oldFree.ival, newFree.ival, memory_order_acq_rel, memory_order_acquire)) {
node = oldFree.ptr;
stpcGetLocalStats(proxy)->reuse++;
break;
}
}
if (node == NULL && alloc) {
int oldNum = atomic_load_explicit(&proxy->numNodes, memory_order_relaxed);
while (oldNum < proxy->maxNodes && !atomic_compare_exchange_strong_explicit(&proxy->numNodes, &oldNum, oldNum + 1, memory_order_relaxed, memory_order_relaxed));
if (oldNum >= proxy->maxNodes)
return NULL;
node = proxy->allocMem(sizeof(stpcNode));
if (node == NULL)
return NULL;
}
memset(node, 0, sizeof(stpcNode));
return node;
}
void
exchange (atomic_int *i)
{
int r;
atomic_compare_exchange_strong_explicit (i, &r, 0, memory_order_seq_cst, memory_order_release); /* { dg-warning "invalid failure memory" } */
atomic_compare_exchange_strong_explicit (i, &r, 0, memory_order_seq_cst, memory_order_acq_rel); /* { dg-warning "invalid failure memory" } */
atomic_compare_exchange_strong_explicit (i, &r, 0, memory_order_relaxed, memory_order_consume); /* { dg-warning "failure memory model cannot be stronger" } */
atomic_compare_exchange_weak_explicit (i, &r, 0, memory_order_seq_cst, memory_order_release); /* { dg-warning "invalid failure memory" } */
atomic_compare_exchange_weak_explicit (i, &r, 0, memory_order_seq_cst, memory_order_acq_rel); /* { dg-warning "invalid failure memory" } */
atomic_compare_exchange_weak_explicit (i, &r, 0, memory_order_relaxed, memory_order_consume); /* { dg-warning "failure memory model cannot be stronger" } */
}
void enqueue(queue_t *q, unsigned int val)
{
std::string str1("enqueue"); //ANNOTATION
function_call(str1, INVOCATION, val); //ANNOTATION
int success = 0;
unsigned int node;
pointer tail;
pointer next;
pointer tmp;
node = new_node();
store_32(&q->nodes[node].value, val);
tmp = atomic_load_explicit(&q->nodes[node].next, memory_order_seq_cst);
set_ptr(&tmp, 0); // NULL
atomic_store_explicit(&q->nodes[node].next, tmp, memory_order_seq_cst);
while (!success) {
tail = atomic_load_explicit(&q->tail, memory_order_seq_cst);
next = atomic_load_explicit(&q->nodes[get_ptr(tail)].next, memory_order_seq_cst);
if (tail == atomic_load_explicit(&q->tail, memory_order_seq_cst)) {
/* Check for uninitialized 'next' */
MODEL_ASSERT(get_ptr(next) != POISON_IDX);
if (get_ptr(next) == 0) { // == NULL
pointer value = MAKE_POINTER(node, get_count(next) + 1);
success = atomic_compare_exchange_strong_explicit(&q->nodes[get_ptr(tail)].next,
&next, value, memory_order_seq_cst, memory_order_seq_cst);
}
if (!success) {
unsigned int ptr = get_ptr(atomic_load_explicit(&q->nodes[get_ptr(tail)].next, memory_order_seq_cst));
pointer value = MAKE_POINTER(ptr,
get_count(tail) + 1);
atomic_compare_exchange_strong_explicit(&q->tail,
&tail, value,
memory_order_seq_cst, memory_order_seq_cst);
thrd_yield();
}
}
}
atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(node, get_count(tail) + 1),
memory_order_seq_cst, memory_order_seq_cst);
function_call(str1, RESPONSE); //ANNOTATION
}
void _queueNode(stpcProxy* proxy, stpcNode* newNode) {
sequencedPtr oldTail;
sequencedPtr newTail;
stpcNode *tailNode, *next;
bool rc, rc2;
long attempts = 0;
newNode->count = GUARD_BIT + 2 * REFERENCE;
/*
* monkey through the trees queuing trick
*/
newTail.ptr = newNode;
newTail.sequence = 0;
oldTail.ival = atomic_load_explicit(&proxy->tail.ival, memory_order_consume);
do {
attempts++;
}
while (!atomic_compare_exchange_strong_explicit(&proxy->tail.ival, &oldTail.ival, newTail.ival, memory_order_acq_rel, memory_order_acquire));
atomic_store_explicit(&oldTail.ptr->next, newNode, memory_order_relaxed);
// update old node's reference count by number of acquired references, clear guard bit, and drop ref acquired from tail pointer
_dropProxyNodeReference(proxy, oldTail.ptr, (oldTail.sequence - GUARD_BIT));
stats_t *stats = stpcGetLocalStats(proxy);
stats->tries++; // _addNode invocations
stats->attempts += attempts; // tail enqueue attempts
}
/* Test for consistency on sizes 1, 2, 4, 8, 16 and 32. */
int
main ()
{
test_struct c;
atomic_store_explicit (&a, zero, memory_order_relaxed);
if (memcmp (&a, &zero, size))
abort ();
c = atomic_exchange_explicit (&a, ones, memory_order_seq_cst);
if (memcmp (&c, &zero, size))
abort ();
if (memcmp (&a, &ones, size))
abort ();
b = atomic_load_explicit (&a, memory_order_relaxed);
if (memcmp (&b, &ones, size))
abort ();
if (!atomic_compare_exchange_strong_explicit (&a, &b, zero, memory_order_seq_cst, memory_order_acquire))
abort ();
if (memcmp (&a, &zero, size))
abort ();
if (atomic_compare_exchange_weak_explicit (&a, &b, ones, memory_order_seq_cst, memory_order_acquire))
abort ();
if (memcmp (&b, &zero, size))
abort ();
return 0;
}
static noreturn void thread_entry(cloudabi_tid_t tid, void *data) {
// Set up TLS space.
char tls_space[tls_size()];
char *tls_start = tls_addr(tls_space);
memcpy(tls_start, __pt_tls_vaddr_abs, __pt_tls_filesz);
memset(tls_start + __pt_tls_filesz, '\0',
__pt_tls_memsz_aligned - __pt_tls_filesz);
tls_replace(tls_space);
// Fix up some of the variables stored in TLS.
pthread_t handle = data;
__pthread_self_object = handle;
__pthread_thread_id = tid;
__safestack_unsafe_stack_ptr = (void *)__rounddown(
(uintptr_t)handle->unsafe_stack + handle->unsafe_stacksize,
PTHREAD_UNSAFE_STACK_ALIGNMENT);
// Initialize the the once object used for joining. This is also done
// by the parent, but it may be the case that we call pthread_exit()
// before the parent has a chance to initialize it.
cloudabi_lock_t expected = CLOUDABI_LOCK_BOGUS;
atomic_compare_exchange_strong_explicit(
&handle->join, &expected, tid | CLOUDABI_LOCK_WRLOCKED,
memory_order_acquire, memory_order_relaxed);
// Free thread startup information and invoke user-supplied start routine.
void *(*start_routine)(void *) = handle->start_routine;
void *argument = handle->argument;
pthread_exit(start_routine(argument));
}
int take(Deque *q) {
std::string str1("pop_back"); //ANNOTATION
function_call(str1, INVOCATION); //ANNOTATION
size_t b = atomic_load_explicit(&q->bottom, memory_order_seq_cst) - 1;
Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_seq_cst);
atomic_store_explicit(&q->bottom, b, memory_order_seq_cst); //relaxed
atomic_thread_fence(memory_order_seq_cst);
size_t t = atomic_load_explicit(&q->top, memory_order_seq_cst);
int x;
if (t <= b) {
/* Non-empty queue. */
x = atomic_load_explicit(&a->buffer[b % atomic_load_explicit(&a->size,memory_order_seq_cst)], memory_order_seq_cst);
if (t == b) {
/* Single last element in queue. */
if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_seq_cst))
/* Failed race. */
x = EMPTY;
atomic_store_explicit(&q->bottom, b + 1, memory_order_seq_cst); //relaxed
}
} else { /* Empty queue. */
x = EMPTY;
atomic_store_explicit(&q->bottom, b + 1, memory_order_seq_cst); // relaxed
}
//if(x == EMPTY)
//function_call(str1, RESPONSE, (uint64_t) NULL); //ANNOTATION
//else
function_call(str1, RESPONSE, (uint64_t) x); //ANNOTATION
return x;
}
bool dequeue(queue_t *q, unsigned int *retVal)
{
std::string str1("dequeue"); //ANNOTATION
function_call(str1, INVOCATION); //ANNOTATION
int success = 0;
pointer head;
pointer tail;
pointer next;
while (!success) {
head = atomic_load_explicit(&q->head, memory_order_seq_cst);
tail = atomic_load_explicit(&q->tail, memory_order_seq_cst);
next = atomic_load_explicit(&q->nodes[get_ptr(head)].next, memory_order_seq_cst);
if (atomic_load_explicit(&q->head, memory_order_seq_cst) == head) {
if (get_ptr(head) == get_ptr(tail)) {
/* Check for uninitialized 'next' */
MODEL_ASSERT(get_ptr(next) != POISON_IDX);
if (get_ptr(next) == 0) { // NULL
function_call(str1, RESPONSE); //ANNOTATION
return false; // NULL
}
atomic_compare_exchange_strong_explicit(&q->tail,
&tail,
MAKE_POINTER(get_ptr(next), get_count(tail) + 1),
memory_order_seq_cst, memory_order_seq_cst);
thrd_yield();
} else {
*retVal = load_32(&q->nodes[get_ptr(next)].value);
success = atomic_compare_exchange_strong_explicit(&q->head,
&head,
MAKE_POINTER(get_ptr(next), get_count(head) + 1),
memory_order_seq_cst, memory_order_seq_cst);
if (!success)
thrd_yield();
}
}
}
reclaim(get_ptr(head));
function_call(str1, RESPONSE, *retVal); //ANNOTATION
return true;
}
static _Bool
SetNextSegment(
_In_ SystemPipeSegment_t* Segment,
_In_ SystemPipeSegment_t* Next)
{
SystemPipeSegment_t* Expected = NULL;
return atomic_compare_exchange_strong_explicit(&Segment->Link, &Expected, Next,
memory_order_release, memory_order_relaxed);
}
static inline _Bool
SwapSystemPipeHead(
_In_ SystemPipe_t* Pipe,
_In_ SystemPipeSegment_t** Segment,
_In_ SystemPipeSegment_t* Next)
{
assert(Pipe->Configuration & PIPE_MULTIPLE_CONSUMERS);
return atomic_compare_exchange_strong_explicit(&Pipe->ConsumerState.Head,
Segment, Next, memory_order_release, memory_order_acquire);
}
static inline _Bool
SwapSystemPipeTail(
_In_ SystemPipe_t* Pipe,
_In_ SystemPipeSegment_t** Segment,
_In_ SystemPipeSegment_t* Next)
{
assert((Pipe->Configuration & PIPE_MPMC) != 0);
return atomic_compare_exchange_strong_explicit(&Pipe->ProducerState.Tail,
Segment, Next, memory_order_release, memory_order_relaxed);
}
TEST(stdatomic, atomic_compare_exchange) {
atomic_int i;
int expected;
atomic_store(&i, 123);
expected = 123;
ASSERT_TRUE(atomic_compare_exchange_strong(&i, &expected, 456));
ASSERT_FALSE(atomic_compare_exchange_strong(&i, &expected, 456));
ASSERT_EQ(456, expected);
atomic_store(&i, 123);
expected = 123;
ASSERT_TRUE(atomic_compare_exchange_strong_explicit(&i, &expected, 456, memory_order_relaxed,
memory_order_relaxed));
ASSERT_FALSE(atomic_compare_exchange_strong_explicit(&i, &expected, 456, memory_order_relaxed,
memory_order_relaxed));
ASSERT_EQ(456, expected);
atomic_store(&i, 123);
expected = 123;
int iter_count = 0;
do {
++iter_count;
ASSERT_LT(iter_count, 100); // Arbitrary limit on spurious compare_exchange failures.
ASSERT_EQ(expected, 123);
} while(!atomic_compare_exchange_weak(&i, &expected, 456));
ASSERT_FALSE(atomic_compare_exchange_weak(&i, &expected, 456));
ASSERT_EQ(456, expected);
atomic_store(&i, 123);
expected = 123;
iter_count = 0;
do {
++iter_count;
ASSERT_LT(iter_count, 100);
ASSERT_EQ(expected, 123);
} while(!atomic_compare_exchange_weak_explicit(&i, &expected, 456, memory_order_relaxed,
memory_order_relaxed));
ASSERT_FALSE(atomic_compare_exchange_weak_explicit(&i, &expected, 456, memory_order_relaxed,
memory_order_relaxed));
ASSERT_EQ(456, expected);
}
int pthread_mutex_destroy(pthread_mutex_t* mutex_interface) {
pthread_mutex_internal_t* mutex = __get_internal_mutex(mutex_interface);
uint16_t old_state = atomic_load_explicit(&mutex->state, memory_order_relaxed);
// Store 0xffff to make the mutex unusable. Although POSIX standard says it is undefined
// behavior to destroy a locked mutex, we prefer not to change mutex->state in that situation.
if (MUTEX_STATE_BITS_IS_UNLOCKED(old_state) &&
atomic_compare_exchange_strong_explicit(&mutex->state, &old_state, 0xffff,
memory_order_relaxed, memory_order_relaxed)) {
return 0;
}
return EBUSY;
}
static inline __always_inline int __pthread_normal_mutex_trylock(pthread_mutex_internal_t* mutex,
uint16_t shared) {
const uint16_t unlocked = shared | MUTEX_STATE_BITS_UNLOCKED;
const uint16_t locked_uncontended = shared | MUTEX_STATE_BITS_LOCKED_UNCONTENDED;
uint16_t old_state = unlocked;
if (__predict_true(atomic_compare_exchange_strong_explicit(&mutex->state, &old_state,
locked_uncontended, memory_order_acquire, memory_order_relaxed))) {
return 0;
}
return EBUSY;
}
/**
* Unset thread specific value if present
*
* @return true on success
*/
bool erase() {
auto currThread = current_thread();
for (size_t i = 0; i < N; i++) {
if (atomic_load_explicit(&threads[i], memory_order_acquire) == currThread) {
values[i] = {};
thread_t nullThread = nullptr;
return atomic_compare_exchange_strong_explicit(&threads[i], &currThread,
nullThread, memory_order_acq_rel, memory_order_acq_rel);
}
}
return false;
}
stpcNode* stpcGetProxyNodeReference(stpcProxy* proxy) {
sequencedPtr oldTail;
sequencedPtr newTail;
oldTail.ival = atomic_load_explicit(&proxy->tail.ival, memory_order_relaxed);
do {
newTail.sequence = oldTail.sequence + REFERENCE;
newTail.ptr = oldTail.ptr;
}
while (!atomic_compare_exchange_strong_explicit(&proxy->tail.ival, &oldTail.ival, newTail.ival, memory_order_relaxed, memory_order_relaxed));
return oldTail.ptr;
}
void pony_asio_event_subscribe(asio_event_t* ev)
{
if((ev == NULL) ||
(ev->flags == ASIO_DISPOSABLE) ||
(ev->flags == ASIO_DESTROYED))
return;
asio_backend_t* b = ponyint_asio_get_backend();
if(ev->noisy)
ponyint_asio_noisy_add();
struct epoll_event ep;
ep.data.ptr = ev;
ep.events = EPOLLRDHUP | EPOLLET;
if(ev->flags & ASIO_READ)
ep.events |= EPOLLIN;
if(ev->flags & ASIO_WRITE)
ep.events |= EPOLLOUT;
if(ev->flags & ASIO_TIMER)
{
ev->fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
timer_set_nsec(ev->fd, ev->nsec);
ep.events |= EPOLLIN;
}
if(ev->flags & ASIO_SIGNAL)
{
int sig = (int)ev->nsec;
asio_event_t* prev = NULL;
if((sig < MAX_SIGNAL) &&
atomic_compare_exchange_strong_explicit(&b->sighandlers[sig], &prev, ev,
memory_order_release, memory_order_relaxed))
{
signal(sig, signal_handler);
ev->fd = eventfd(0, EFD_NONBLOCK);
ep.events |= EPOLLIN;
} else {
return;
}
}
epoll_ctl(b->epfd, EPOLL_CTL_ADD, ev->fd, &ep);
}
bool ponyint_messageq_markempty(messageq_t* q)
{
pony_msg_t* tail = q->tail;
pony_msg_t* head = atomic_load_explicit(&q->head, memory_order_relaxed);
if(((uintptr_t)head & 1) != 0)
return true;
if(head != tail)
return false;
head = (pony_msg_t*)((uintptr_t)head | 1);
return atomic_compare_exchange_strong_explicit(&q->head, &tail, head,
memory_order_release, memory_order_relaxed);
}
void pony_asio_event_unsubscribe(asio_event_t* ev)
{
if((ev == NULL) ||
(ev->flags == ASIO_DISPOSABLE) ||
(ev->flags == ASIO_DESTROYED))
return;
asio_backend_t* b = ponyint_asio_get_backend();
if(ev->noisy)
{
ponyint_asio_noisy_remove();
ev->noisy = false;
}
epoll_ctl(b->epfd, EPOLL_CTL_DEL, ev->fd, NULL);
if(ev->flags & ASIO_TIMER)
{
if(ev->fd != -1)
{
close(ev->fd);
ev->fd = -1;
}
}
if(ev->flags & ASIO_SIGNAL)
{
int sig = (int)ev->nsec;
asio_event_t* prev = ev;
if((sig < MAX_SIGNAL) &&
atomic_compare_exchange_strong_explicit(&b->sighandlers[sig], &prev, NULL,
memory_order_release, memory_order_relaxed))
{
signal(sig, SIG_DFL);
close(ev->fd);
ev->fd = -1;
}
}
ev->flags = ASIO_DISPOSABLE;
send_request(ev, ASIO_DISPOSABLE);
}
bool ponyint_messageq_markempty(messageq_t* q)
{
pony_msg_t* tail = q->tail;
pony_msg_t* head = atomic_load_explicit(&q->head, memory_order_relaxed);
if(((uintptr_t)head & 1) != 0)
return true;
if(head != tail)
return false;
head = (pony_msg_t*)((uintptr_t)head | 1);
#ifdef USE_VALGRIND
ANNOTATE_HAPPENS_BEFORE(&q->head);
#endif
return atomic_compare_exchange_strong_explicit(&q->head, &tail, head,
memory_order_release, memory_order_relaxed);
}
int pthread_mutex_trylock(pthread_mutex_t* mutex_interface) {
pthread_mutex_internal_t* mutex = __get_internal_mutex(mutex_interface);
uint16_t old_state = atomic_load_explicit(&mutex->state, memory_order_relaxed);
uint16_t mtype = (old_state & MUTEX_TYPE_MASK);
uint16_t shared = (old_state & MUTEX_SHARED_MASK);
const uint16_t unlocked = mtype | shared | MUTEX_STATE_BITS_UNLOCKED;
const uint16_t locked_uncontended = mtype | shared | MUTEX_STATE_BITS_LOCKED_UNCONTENDED;
// Handle common case first.
if (__predict_true(mtype == MUTEX_TYPE_BITS_NORMAL)) {
return __pthread_normal_mutex_trylock(mutex, shared);
}
// Do we already own this recursive or error-check mutex?
pid_t tid = __get_thread()->tid;
if (tid == atomic_load_explicit(&mutex->owner_tid, memory_order_relaxed)) {
if (mtype == MUTEX_TYPE_BITS_ERRORCHECK) {
return EBUSY;
}
return __recursive_increment(mutex, old_state);
}
// Same as pthread_mutex_lock, except that we don't want to wait, and
// the only operation that can succeed is a single compare_exchange to acquire the
// lock if it is released / not owned by anyone. No need for a complex loop.
// If exchanged successfully, an acquire fence is required to make
// all memory accesses made by other threads visible to the current CPU.
old_state = unlocked;
if (__predict_true(atomic_compare_exchange_strong_explicit(&mutex->state, &old_state,
locked_uncontended,
memory_order_acquire,
memory_order_relaxed))) {
atomic_store_explicit(&mutex->owner_tid, tid, memory_order_relaxed);
return 0;
}
return EBUSY;
}
/**
* Set or overwrite thread specific value
*
* @param value value to store
*
* @return true on success
*/
bool set(T value) {
auto currThread = current_thread();
T *ptr = nullptr;
// Find previous value if any
for (size_t i = 0; ptr == nullptr && i < N; i++)
if (atomic_load_explicit(&threads[i], memory_order_acquire) == currThread)
ptr = &values[i];
// Find null value if any
for (size_t i = 0; ptr == nullptr && i < N; i++) {
thread_t nullThread = nullptr;
if (atomic_compare_exchange_strong_explicit(&threads[i], &nullThread, currThread,
memory_order_acq_rel, memory_order_acq_rel))
ptr = &values[i];
}
// Insert if we can
if (ptr) *ptr = value;
return ptr != nullptr;
}
/**
* Update speed meter.
* @param[in] speed
* @param[in] count
*/
void spdm_update(struct speed_meter *speed, uint64_t count)
{
uint64_t curr_time = zclock(false);
uint64_t last_update = atomic_load_explicit(&speed->last_update, memory_order_acquire);
if (curr_time - last_update >= SEC2USEC(1)) {
if (atomic_compare_exchange_strong_explicit(&speed->last_update, &last_update, curr_time, memory_order_release,
memory_order_relaxed)) {
size_t i = atomic_load_explicit(&speed->i, memory_order_acquire);
uint64_t speed_aux = atomic_load_explicit(&speed->speed_aux, memory_order_acquire);
atomic_store_explicit(&speed->backlog[i].speed, speed_aux, memory_order_release);
atomic_fetch_sub_explicit(&speed->speed_aux, speed_aux, memory_order_release);
atomic_store_explicit(&speed->backlog[i].timestamp, last_update, memory_order_release);
i++;
if (SPEED_METER_BACKLOG == i) {
i = 0;
}
atomic_store_explicit(&speed->i, i, memory_order_release);
}
}
atomic_fetch_add_explicit(&speed->speed_aux, count, memory_order_release);
}
void BBinder::attachObject(
const void* objectID, void* object, void* cleanupCookie,
object_cleanup_func func)
{
Extras* e = reinterpret_cast<Extras*>(
atomic_load_explicit(&mExtras, std::memory_order_acquire));
if (!e) {
e = new Extras;
uintptr_t expected = 0;
if (!atomic_compare_exchange_strong_explicit(
&mExtras, &expected,
reinterpret_cast<uintptr_t>(e),
std::memory_order_release,
std::memory_order_acquire)) {
delete e;
e = reinterpret_cast<Extras*>(expected); // Filled in by CAS
}
if (e == 0) return; // out of memory
}
AutoMutex _l(e->mLock);
e->mObjects.attach(objectID, object, cleanupCookie, func);
}
int steal(Deque *q) {
std::string str1("pop_front"); //ANNOTATION
function_call(str1, INVOCATION); //ANNOTATION
size_t t = atomic_load_explicit(&q->top, memory_order_seq_cst); //acquire
atomic_thread_fence(memory_order_seq_cst);
size_t b = atomic_load_explicit(&q->bottom, memory_order_seq_cst); //acquire
int x = EMPTY;
if (t < b) {
/* Non-empty queue. */
Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_seq_cst);
x = atomic_load_explicit(&a->buffer[t % atomic_load_explicit(&a->size, memory_order_seq_cst)], memory_order_seq_cst);
if (!atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1, memory_order_seq_cst, memory_order_seq_cst))
{
function_call(str1, RESPONSE, (uint64_t) ABORT); //ANNOTATION
/* Failed race. */
return ABORT;
}
}
//if(x == EMPTY)
//function_call(str1, RESPONSE, (uint64_t) NULL); //ANNOTATION
//else
function_call(str1, RESPONSE, (uint64_t) x); //ANNOTATION
return x;
}
static int __pthread_mutex_lock_with_timeout(pthread_mutex_internal_t* mutex,
bool use_realtime_clock,
const timespec* abs_timeout_or_null) {
uint16_t old_state = atomic_load_explicit(&mutex->state, memory_order_relaxed);
uint16_t mtype = (old_state & MUTEX_TYPE_MASK);
uint16_t shared = (old_state & MUTEX_SHARED_MASK);
// Handle common case first.
if ( __predict_true(mtype == MUTEX_TYPE_BITS_NORMAL) ) {
return __pthread_normal_mutex_lock(mutex, shared, use_realtime_clock, abs_timeout_or_null);
}
// Do we already own this recursive or error-check mutex?
pid_t tid = __get_thread()->tid;
if (tid == atomic_load_explicit(&mutex->owner_tid, memory_order_relaxed)) {
if (mtype == MUTEX_TYPE_BITS_ERRORCHECK) {
return EDEADLK;
}
return __recursive_increment(mutex, old_state);
}
const uint16_t unlocked = mtype | shared | MUTEX_STATE_BITS_UNLOCKED;
const uint16_t locked_uncontended = mtype | shared | MUTEX_STATE_BITS_LOCKED_UNCONTENDED;
const uint16_t locked_contended = mtype | shared | MUTEX_STATE_BITS_LOCKED_CONTENDED;
// First, if the mutex is unlocked, try to quickly acquire it.
// In the optimistic case where this works, set the state to locked_uncontended.
if (old_state == unlocked) {
// If exchanged successfully, an acquire fence is required to make
// all memory accesses made by other threads visible to the current CPU.
if (__predict_true(atomic_compare_exchange_strong_explicit(&mutex->state, &old_state,
locked_uncontended, memory_order_acquire, memory_order_relaxed))) {
atomic_store_explicit(&mutex->owner_tid, tid, memory_order_relaxed);
return 0;
}
}
ScopedTrace trace("Contending for pthread mutex");
while (true) {
if (old_state == unlocked) {
// NOTE: We put the state to locked_contended since we _know_ there
// is contention when we are in this loop. This ensures all waiters
// will be unlocked.
// If exchanged successfully, an acquire fence is required to make
// all memory accesses made by other threads visible to the current CPU.
if (__predict_true(atomic_compare_exchange_weak_explicit(&mutex->state,
&old_state, locked_contended,
memory_order_acquire,
memory_order_relaxed))) {
atomic_store_explicit(&mutex->owner_tid, tid, memory_order_relaxed);
return 0;
}
continue;
} else if (MUTEX_STATE_BITS_IS_LOCKED_UNCONTENDED(old_state)) {
// We should set it to locked_contended beforing going to sleep. This can make
// sure waiters will be woken up eventually.
int new_state = MUTEX_STATE_BITS_FLIP_CONTENTION(old_state);
if (__predict_false(!atomic_compare_exchange_weak_explicit(&mutex->state,
&old_state, new_state,
memory_order_relaxed,
memory_order_relaxed))) {
continue;
}
old_state = new_state;
}
int result = check_timespec(abs_timeout_or_null, true);
if (result != 0) {
return result;
}
// We are in locked_contended state, sleep until someone wakes us up.
if (__recursive_or_errorcheck_mutex_wait(mutex, shared, old_state, use_realtime_clock,
abs_timeout_or_null) == -ETIMEDOUT) {
return ETIMEDOUT;
}
old_state = atomic_load_explicit(&mutex->state, memory_order_relaxed);
}
}
PONY_API void pony_asio_event_unsubscribe(asio_event_t* ev)
{
if((ev == NULL) ||
(ev->flags == ASIO_DISPOSABLE) ||
(ev->flags == ASIO_DESTROYED))
{
pony_assert(0);
return;
}
asio_backend_t* b = ponyint_asio_get_backend();
pony_assert(b != NULL);
if(ev->noisy)
{
uint64_t old_count = ponyint_asio_noisy_remove();
// tell scheduler threads that asio has no noisy actors
// if the old_count was 1
if (old_count == 1)
{
ponyint_sched_unnoisy_asio(SPECIAL_THREADID_EPOLL);
// maybe wake up a scheduler thread if they've all fallen asleep
ponyint_sched_maybe_wakeup_if_all_asleep(-1);
}
ev->noisy = false;
}
epoll_ctl(b->epfd, EPOLL_CTL_DEL, ev->fd, NULL);
if(ev->flags & ASIO_TIMER)
{
if(ev->fd != -1)
{
close(ev->fd);
ev->fd = -1;
}
}
if(ev->flags & ASIO_SIGNAL)
{
int sig = (int)ev->nsec;
asio_event_t* prev = ev;
#ifdef USE_VALGRIND
ANNOTATE_HAPPENS_BEFORE(&b->sighandlers[sig]);
#endif
if((sig < MAX_SIGNAL) &&
atomic_compare_exchange_strong_explicit(&b->sighandlers[sig], &prev, NULL,
memory_order_release, memory_order_relaxed))
{
struct sigaction new_action;
#if !defined(USE_SCHEDULER_SCALING_PTHREADS)
// Make sure we ignore signals related to scheduler sleeping/waking
// as the default for those signals is termination
if(sig == PONY_SCHED_SLEEP_WAKE_SIGNAL)
new_action.sa_handler = empty_signal_handler;
else
#endif
new_action.sa_handler = SIG_DFL;
sigemptyset (&new_action.sa_mask);
// ask to restart interrupted syscalls to match `signal` behavior
new_action.sa_flags = SA_RESTART;
sigaction(sig, &new_action, NULL);
close(ev->fd);
ev->fd = -1;
}
}
ev->flags = ASIO_DISPOSABLE;
send_request(ev, ASIO_DISPOSABLE);
}
PONY_API void pony_asio_event_subscribe(asio_event_t* ev)
{
if((ev == NULL) ||
(ev->flags == ASIO_DISPOSABLE) ||
(ev->flags == ASIO_DESTROYED))
{
pony_assert(0);
return;
}
asio_backend_t* b = ponyint_asio_get_backend();
pony_assert(b != NULL);
if(ev->noisy)
{
uint64_t old_count = ponyint_asio_noisy_add();
// tell scheduler threads that asio has at least one noisy actor
// if the old_count was 0
if (old_count == 0)
ponyint_sched_noisy_asio(SPECIAL_THREADID_EPOLL);
}
struct epoll_event ep;
ep.data.ptr = ev;
ep.events = EPOLLRDHUP;
if(ev->flags & ASIO_READ)
ep.events |= EPOLLIN;
if(ev->flags & ASIO_WRITE)
ep.events |= EPOLLOUT;
if(ev->flags & ASIO_TIMER)
{
ev->fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
timer_set_nsec(ev->fd, ev->nsec);
ep.events |= EPOLLIN;
}
if(ev->flags & ASIO_SIGNAL)
{
int sig = (int)ev->nsec;
asio_event_t* prev = NULL;
#ifdef USE_VALGRIND
ANNOTATE_HAPPENS_BEFORE(&b->sighandlers[sig]);
#endif
if((sig < MAX_SIGNAL) &&
atomic_compare_exchange_strong_explicit(&b->sighandlers[sig], &prev, ev,
memory_order_release, memory_order_relaxed))
{
struct sigaction new_action;
new_action.sa_handler = signal_handler;
sigemptyset (&new_action.sa_mask);
// ask to restart interrupted syscalls to match `signal` behavior
new_action.sa_flags = SA_RESTART;
sigaction(sig, &new_action, NULL);
ev->fd = eventfd(0, EFD_NONBLOCK);
ep.events |= EPOLLIN;
} else {
return;
}
}
if(ev->flags & ASIO_ONESHOT)
{
ep.events |= EPOLLONESHOT;
} else {
// Only use edge triggering if one shot isn't enabled.
// This is because of how the runtime gets notifications
// from epoll in this ASIO thread and then notifies the
// appropriate actor to read/write as necessary.
// specifically, it seems there's an edge case/race condition
// with edge triggering where if there is already data waiting
// on the socket, then epoll might not be triggering immediately
// when an edge triggered epoll request is made.
ep.events |= EPOLLET;
}
epoll_ctl(b->epfd, EPOLL_CTL_ADD, ev->fd, &ep);
}
