/*! Tries to acquires LOCK and returns true if successful or false
on failure. The lock must not already be held by the current
thread.
This function will not sleep, so it may be called within an
interrupt handler. */
bool lock_try_acquire(struct lock *lock) {
bool success;
ASSERT(lock != NULL);
ASSERT(!lock_held_by_current_thread(lock));
success = sema_try_down(&lock->semaphore);
if (success)
lock->holder = thread_current();
return success;
}
/* Tries to acquires LOCK and returns true if successful or false
on failure. The lock must not already be held by the current
thread.
This function will not sleep, so it may be called within an
interrupt handler. */
bool
lock_try_acquire (struct lock *lock)
{
bool success;
ASSERT (lock != NULL);
ASSERT (!lock_held_by_current_thread (lock));
success = sema_try_down (&lock->semaphore);
//if (success){
// lock->holder = thread_current ();
// list_push_back(&thread_current ()->lock_list,&lock->elem);
// }
return success;
}
/* Tries to acquires LOCK and returns true if successful or false
on failure. The lock must not already be held by the current
thread.
This function will not sleep, so it may be called within an
interrupt handler. */
bool
lock_try_acquire (struct lock *lock)
{
bool success;
ASSERT (lock != NULL);
ASSERT (!lock_held_by_current_thread (lock));
success = sema_try_down (&lock->semaphore);
if (success)
{
lock->holder = thread_current ();
list_push_back (&(lock->holder->hold_locks), &lock->hold_elem);
}
return success;
}
/*
--------------------------------------------------------------------
Tries to acquires LOCK and returns true if successful or false
on failure. The lock must not already be held by the current
thread.
This function will not sleep, so it may be called within an
interrupt handler.
NOTE: we add code to ensure that if the thread is successful
in aquiring the lock it is trying to aquire, that the lock
is then added to the threads list of locks_held, so that the
system of proirity donation stays in tact.
--------------------------------------------------------------------
*/
bool
lock_try_acquire (struct lock *lock)
{
bool success;
ASSERT (lock != NULL);
ASSERT (!lock_held_by_current_thread (lock));
success = sema_try_down (&lock->semaphore);
if (success) {
if (!thread_mlfqs) {
lock->priority = PRI_MIN;
list_push_front(&(thread_current()->locks_held), &(lock->elem));
thread_current()->lock_waiting_on = NULL;
}
lock->holder = thread_current ();
}
return success;
}
/* Tries to acquires LOCK and returns true if successful or false
on failure. The lock must not already be held by the current
thread.
This function will not sleep, so it may be called within an
interrupt handler. */
bool
lock_try_acquire (struct lock *lock)
{
bool success;
ASSERT (lock != NULL);
ASSERT (!lock_held_by_current_thread (lock));
enum intr_level old_level = intr_disable ();
success = sema_try_down (&lock->semaphore);
if (success)
{
/* If the lock can be acquired, then the current thread
is not waiting for it anymore. */
thread_current ()->lock_to_acquire = NULL;
lock->holder = thread_current ();
}
intr_set_level (old_level);
return success;
}
/* Acquires LOCK, sleeping until it becomes available if
necessary. The lock must not already be held by the current
thread.
This function may sleep, so it must not be called within an
interrupt handler. This function may be called with
interrupts disabled, but interrupts will be turned back on if
we need to sleep. */
void
lock_acquire (struct lock *lock)
{
ASSERT (lock != NULL);
ASSERT (!intr_context ());
ASSERT (!lock_held_by_current_thread (lock));
if (!sema_try_down (&lock->semaphore))
{
sema_down (&lock->sema_lock);
thread_current ()->wait_lock = lock;
lock_donate_priority(thread_current(), lock);
sema_up (&lock->sema_lock);
sema_down (&lock->semaphore);
}
lock->holder = thread_current ();
list_push_back (&(lock->holder->hold_locks), &lock->hold_elem);
sema_down (&lock->sema_lock);
lock->holder->wait_lock = NULL;
sema_up (&lock->sema_lock);
}
