/* Verifies that lowering a thread’s priority so that it is no
longer the highest-priority thread in the system causes it to
yield immediately. */
#include
#include “tests/threads/tests.h”
#include “threads/init.h”
#include “threads/thread.h”
static thread_func changing_thread;
void
test_priority_change(void)
{
/* This test does not work with the MLFQS. */
ASSERT(!thread_mlfqs);
msg(“Creating a high-priority thread 2.”);
thread_create(“thread 2”, PRI_DEFAULT + 1, changing_thread, NULL);
msg(“Thread 2 should have just lowered its priority.”);
thread_set_priority(PRI_DEFAULT – 2);
msg(“Thread 2 should have just exited.”);
}
static void
changing_thread(void *aux UNUSED)
{
msg(“Thread 2 now lowering priority.”);
thread_set_priority(PRI_DEFAULT – 1);
msg(“Thread 2 exiting.”);
}