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/* Basically that's the same test as priority-donate-sema but using
conditions instead of semaphores.
Low priority thread L acquires a lock, then blocks waiting for
the condition. Medium priority thread M then blocks waiting for
the same condition. Next, high priority thread H attempts to
acquire the lock, donating its priority to L.
Next, the main thread signals the condition, waking up L. L
releases the lock, which wakes up H. H signals the condition,
waking up M. H terminates, then M, then L, and finally the
main thread.
Written by Manuel Mausz <manuel-tuwien@mausz.at>. */
#include <stdio.h>
#include "tests/threads/tests.h"
#include "threads/init.h"
#include "threads/synch.h"
#include "threads/thread.h"
struct lock_and_cond
{
struct lock lock;
struct lock lockc;
struct condition cond;
};
static thread_func l_thread_func;
static thread_func m_thread_func;
static thread_func h_thread_func;
void
test_priority_donate_condvar (void)
{
struct lock_and_cond ls;
/* This test does not work with the MLFQS. */
ASSERT (!thread_mlfqs);
/* Make sure our priority is the default. */
ASSERT (thread_get_priority () == PRI_DEFAULT);
lock_init (&ls.lock);
lock_init (&ls.lockc);
cond_init (&ls.cond);
thread_create ("low", PRI_DEFAULT + 1, l_thread_func, &ls);
thread_create ("med", PRI_DEFAULT + 3, m_thread_func, &ls);
thread_create ("high", PRI_DEFAULT + 5, h_thread_func, &ls);
lock_acquire (&ls.lockc);
msg ("Signaling...");
cond_signal (&ls.cond, &ls.lockc);
lock_release (&ls.lockc);
msg ("Main thread finished.");
}
static void
l_thread_func (void *ls_)
{
struct lock_and_cond *ls = ls_;
lock_acquire (&ls->lock);
msg ("Thread L acquired lock.");
lock_acquire (&ls->lockc);
cond_wait (&ls->cond, &ls->lockc);
lock_release (&ls->lockc);
msg ("Thread L woke up.");
lock_release (&ls->lock);
msg ("Thread L finished.");
}
static void
m_thread_func (void *ls_)
{
struct lock_and_cond *ls = ls_;
lock_acquire (&ls->lockc);
cond_wait (&ls->cond, &ls->lockc);
lock_release (&ls->lockc);
msg ("Thread M finished.");
}
static void
h_thread_func (void *ls_)
{
struct lock_and_cond *ls = ls_;
lock_acquire (&ls->lock);
msg ("Thread H acquired lock.");
lock_acquire (&ls->lockc);
msg ("Signaling...");
cond_signal (&ls->cond, &ls->lockc);
lock_release (&ls->lockc);
lock_release (&ls->lock);
msg ("Thread H finished.");
}
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