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Update semaphore code to wake highest priority thread, and run if required

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Themis Demetriades
2024-10-15 13:53:48 +01:00
parent 79061fcb9b
commit 6855a48603
1 changed files with 3 additions and 1 deletions
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4
src/threads/synch.c
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@@ -68,7 +68,8 @@ sema_down (struct semaphore *sema)
old_level = intr_disable (); old_level = intr_disable ();
while (sema->value == 0) while (sema->value == 0)
{ {
list_push_back (&sema->waiters, &thread_current ()->elem); list_insert_ordered (&sema->waiters, &thread_current ()->elem,
&thread_priority_greater, NULL);
thread_block (); thread_block ();
} }
sema->value--; sema->value--;
@@ -118,6 +119,7 @@ sema_up (struct semaphore *sema)
struct thread, elem)); struct thread, elem));
sema->value++; sema->value++;
intr_set_level (old_level); intr_set_level (old_level);
thread_yield ();
} }
static void sema_test_helper (void *sema_); static void sema_test_helper (void *sema_);