Implement LinkedListAllocator::size_align

src/allocator/linked_list.rs

@@ -103,6 +103,19 @@ impl LinkedListAllocator {
         // region suitable for allocation
         Ok(alloc_start)
     }
+
+    /// Adjust the given layout so that the resulting allocated memory
+    /// region is also capable of storing a `ListNode`.
+    ///
+    /// Returns the adjusted size and alignment as a (size, align) tuple.
+    fn size_align(layout: Layout) -> (usize, usize) {
+        let layout = layout
+            .align_to(mem::align_of::<ListNode>())
+            .expect("adjusting alignment failed")
+            .pad_to_align();
+        let size = layout.size().max(mem::size_of::<ListNode>());
+        (size, layout.align())
+    }
 }
 
 unsafe impl GlobalAlloc for Locked<LinkedListAllocator> {

src/lib.rs

@@ -4,6 +4,7 @@
 #![feature(abi_x86_interrupt)]
 #![feature(alloc_error_handler)]
 #![feature(const_fn)]
+#![feature(alloc_layout_extra)]
 #![test_runner(crate::test_runner)]
 #![reexport_test_harness_main = "test_main"]