/*
* call-seq:
* mutex.try_lock -> true or false
*
* Attempts to obtain the lock and returns immediately. Returns +true+ if the
* lock was granted.
*/
VALUE
rb_mutex_trylock(VALUE self)
{
rb_mutex_t *mutex;
VALUE locked = Qfalse;
GetMutexPtr(self, mutex);
native_mutex_lock(&mutex->lock);
if (mutex->th == 0) {
rb_thread_t *th = GET_THREAD();
mutex->th = th;
locked = Qtrue;
mutex_locked(th, self);
}
native_mutex_unlock(&mutex->lock);
return locked;
}
/*
* call-seq:
* mutex.lock -> self
*
* Attempts to grab the lock and waits if it isn't available.
* Raises +ThreadError+ if +mutex+ was locked by the current thread.
*/
VALUE
rb_mutex_lock(VALUE self)
{
rb_thread_t *th = GET_THREAD();
rb_mutex_t *mutex;
GetMutexPtr(self, mutex);
/* When running trap handler */
if (!mutex->allow_trap && th->interrupt_mask & TRAP_INTERRUPT_MASK) {
rb_raise(rb_eThreadError, "can't be called from trap context");
}
if (rb_mutex_trylock(self) == Qfalse) {
if (mutex->th == th) {
rb_raise(rb_eThreadError, "deadlock; recursive locking");
}
while (mutex->th != th) {
int interrupted;
enum rb_thread_status prev_status = th->status;
volatile int timeout_ms = 0;
struct rb_unblock_callback oldubf;
set_unblock_function(th, lock_interrupt, mutex, &oldubf, FALSE);
th->status = THREAD_STOPPED_FOREVER;
th->locking_mutex = self;
native_mutex_lock(&mutex->lock);
th->vm->sleeper++;
/*
* Carefully! while some contended threads are in lock_func(),
* vm->sleepr is unstable value. we have to avoid both deadlock
* and busy loop.
*/
if ((vm_living_thread_num(th->vm) == th->vm->sleeper) &&
!patrol_thread) {
timeout_ms = 100;
patrol_thread = th;
}
GVL_UNLOCK_BEGIN();
interrupted = lock_func(th, mutex, (int)timeout_ms);
native_mutex_unlock(&mutex->lock);
GVL_UNLOCK_END();
if (patrol_thread == th)
patrol_thread = NULL;
reset_unblock_function(th, &oldubf);
th->locking_mutex = Qfalse;
if (mutex->th && interrupted == 2) {
rb_check_deadlock(th->vm);
}
if (th->status == THREAD_STOPPED_FOREVER) {
th->status = prev_status;
}
th->vm->sleeper--;
if (mutex->th == th) mutex_locked(th, self);
if (interrupted) {
RUBY_VM_CHECK_INTS_BLOCKING(th);
}
}
}
return self;
}
/** Test whether page tables are locked.
*
* @param as Address space where the page tables belong.
*
* @return True if the page tables belonging to the address soace
* are locked, otherwise false.
*/
bool pt_locked(as_t *as)
{
return mutex_locked(&as->lock);
}