kernel/heap: improve large alignment handling

1 files changed, 10 insertions, 1 deletions

diff --git a/kernel/include/kernel/memory/block_list_allocator.hpp b/kernel/include/kernel/memory/block_list_allocator.hpp
index 977ce89..5e81c44 100644
--- a/kernel/include/kernel/memory/block_list_allocator.hpp
+++ b/kernel/include/kernel/memory/block_list_allocator.hpp
@@ -42,12 +42,21 @@ namespace kernel::memory
   private:
     struct block_header final
     {
-      std::size_t size;
+      std::size_t usable_size;
       bool free;
       block_header * next;
       block_header * prev;
     };
 
+    //! The size of the metadata required for each allocated block.
+    //!
+    //! Each allocated block carries a block header, like any unallocated one, but in addition also has a back-pointer
+    //! to the block header to support padding due to alignment.
+    constexpr auto static allocated_metadata_size = sizeof(block_header) + sizeof(block_header *);
+
+    //! The minimum number of bytes for an allocation.
+    constexpr auto static minimum_allocation_size = 16uz;
+
     //! Try to expand the heap to accommodate the given size.
     //!
     //! @param delta The size to expand the heap by.