Refactor thread recalculate priority to add comments for clarity, w/ T

src/threads/thread.c

@@ -419,12 +419,16 @@ thread_recalculate_priority (void)
   struct thread *t = thread_current ();
   t->priority = t->base_priority;
 
+  /* If there are no donors to the current thread, then the effective
+     priority is just the base priority. */
   if (!list_empty (&t->donors_list))
     {
       int max_donated_priority =
         list_entry (list_max (&t->donors_list, donor_priority_less, NULL),
                     struct thread, donor_elem)->priority;
 
+      /* The effective priority is the max donated priority if this is
+         higher than the base priority. */
       if (max_donated_priority > t->priority)
         t->priority = max_donated_priority;
     }