Merge pull request #8 from richardchien/fix-dealloc

fix buddy `dealloc` bug

Author: jiegec

src/frame.rs

@@ -111,9 +111,6 @@ impl FrameAllocator {
         let size = count.next_power_of_two();
         let class = size.trailing_zeros() as usize;
 
-        // Put back into free list
-        self.free_list[class].insert(frame);
-
         // Merge free buddy lists
         let mut current_ptr = frame;
         let mut current_class = class;
@@ -123,8 +120,8 @@ impl FrameAllocator {
                 // Free buddy found
                 current_ptr = min(current_ptr, buddy);
                 current_class += 1;
-                self.free_list[current_class].insert(current_ptr);
             } else {
+                self.free_list[current_class].insert(current_ptr);
                 break;
             }
         }

src/test.rs

@@ -132,3 +132,16 @@ fn test_frame_allocator_alloc_and_free() {
         frame.dealloc(addr, 512);
     }
 }
+
+#[test]
+fn test_frame_allocator_alloc_and_free_complex() {
+    let mut frame = FrameAllocator::new();
+    frame.add_frame(100, 1024);
+    for _ in 0..10 {
+        let addr = frame.alloc(1).unwrap();
+        frame.dealloc(addr, 1);
+    }
+    let addr1 = frame.alloc(1).unwrap();
+    let addr2 = frame.alloc(1).unwrap();
+    assert_ne!(addr1, addr2);
+}