From 91cef4d650922cc341b7d40fdd7038cde333039e Mon Sep 17 00:00:00 2001
From: sBubshait <s.bobshit@gmail.com>
Date: Wed, 6 Nov 2024 15:36:56 +0000
Subject: [PATCH] Refactor lock release and sema up to remove unnecessary code

---
 src/threads/synch.c | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/threads/synch.c b/src/threads/synch.c
index 09fc71f..d706d19 100644
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -113,28 +113,33 @@ void
 sema_up (struct semaphore *sema)
 {
   enum intr_level old_level;
+  bool thread_unblocked = false; /* Flag to track if any thread was woken up. */
 
   ASSERT (sema != NULL);
 
   old_level = intr_disable ();
   if (!list_empty (&sema->waiters))
-    {
-      /* Enforces wake-up of the highest priority thread waiting for the
-         semaphore. */
-      struct list_elem *e = list_max (&sema->waiters, priority_less, NULL);
-      list_remove (e);
-      thread_unblock (list_entry (e, struct thread, elem));
-    }
+  {
+    /* Enforces wake-up of the highest priority thread waiting for the
+       semaphore. */
+    struct list_elem *e = list_max (&sema->waiters, priority_less, NULL);
+    list_remove (e);
+    thread_unblock (list_entry (e, struct thread, elem));
+    thread_unblocked = true;
+  }
   sema->value++;
   intr_set_level (old_level);
 
   /* Yields the CPU in case the thread that has been woken up has a higher
      priority that the current running thread, including the case when called
      within an interrupt handler. */
-  if (intr_context ())
-    intr_yield_on_return ();
-  else
-    thread_yield ();
+  if (thread_unblocked)
+  {
+    if (intr_context ())
+      intr_yield_on_return ();
+    else
+      thread_yield ();
+  }
 }
 
 static void sema_test_helper (void *sema_);
@@ -347,7 +352,6 @@ lock_release (struct lock *lock)
 
   lock->holder = NULL;
   sema_up (&lock->semaphore);
-  thread_yield ();
 }
 
 /* Returns true if the current thread holds LOCK, false