52 lines
1.5 KiB
C
52 lines
1.5 KiB
C
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/* The main thread acquires a lock. Then it creates a
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higher-priority thread that blocks acquiring the lock, causing
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it to donate their priorities to the main thread. The main
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thread attempts to lower its priority, which should not take
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effect until the donation is released. */
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#include <stdio.h>
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#include "tests/threads/tests.h"
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#include "threads/init.h"
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#include "threads/synch.h"
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#include "threads/thread.h"
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static thread_func acquire_thread_func;
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void
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test_priority_donate_lower (void)
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{
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struct lock lock;
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/* This test does not work with the MLFQS. */
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ASSERT (!thread_mlfqs);
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/* Make sure our priority is the default. */
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ASSERT (thread_get_priority () == PRI_DEFAULT);
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lock_init (&lock);
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lock_acquire (&lock);
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thread_create ("acquire", PRI_DEFAULT + 10, acquire_thread_func, &lock);
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msg ("Main thread should have priority %d. Actual priority: %d.",
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PRI_DEFAULT + 10, thread_get_priority ());
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msg ("Lowering base priority...");
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thread_set_priority (PRI_DEFAULT - 10);
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msg ("Main thread should have priority %d. Actual priority: %d.",
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PRI_DEFAULT + 10, thread_get_priority ());
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lock_release (&lock);
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msg ("acquire must already have finished.");
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msg ("Main thread should have priority %d. Actual priority: %d.",
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PRI_DEFAULT - 10, thread_get_priority ());
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}
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static void
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acquire_thread_func (void *lock_)
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{
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struct lock *lock = lock_;
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lock_acquire (lock);
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msg ("acquire: got the lock");
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lock_release (lock);
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msg ("acquire: done");
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}
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