vault backup: 2025-03-04 08:59:45

Concurrent Systems/notes/Lezione2.md

@@ -56,3 +56,15 @@ How can pi enter its CS?
 
 ![[Pasted image 20250304084901.png]]
 
+Deadlock freedom
+
+Let $p_i$ invoke lock
+- If it eventually wins -> √
+- If it is blocked forever, where can it be blocked?
+	1. In the second wait Y =  ⊥
+		- in this case, it read a value in Y different from i
+		- there is a $p_h$ that wrote Y after $p_i$
+		- let us consider the last of such $p_h \to$ it will eventually win
+	2. In the ∀j.wait FLAG[j] = down
+		- this wait cannot block a process forever
+		- if pj doesn't lock, i