WIP thread safe linked list

3 files changed, 9 insertions, 8 deletions

diff --git a/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp b/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
index 6af6298..e77602c 100644
--- a/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
+++ b/arch/x86_64/include/arch/memory/heap/linked_list_allocator.hpp
@@ -96,9 +96,9 @@ namespace teachos::arch::memory::heap
      */
     auto clear_memory_block_header(void * pointer) -> void;
 
-    std::size_t heap_start;  ///< Start of the allocatable heap area
-    std::size_t heap_end;    ///< End of the allocatable heap area
-    memory_block * first;    ///< First free entry in our memory
+    std::size_t heap_start;             ///< Start of the allocatable heap area
+    std::size_t heap_end;               ///< End of the allocatable heap area
+    std::atomic<memory_block *> first;  ///< First free entry in our memory
   };
 }  // namespace teachos::arch::memory::heap
 
diff --git a/arch/x86_64/include/arch/memory/heap/memory_block.hpp b/arch/x86_64/include/arch/memory/heap/memory_block.hpp
index c48d0cd..1fbbfd5 100644
--- a/arch/x86_64/include/arch/memory/heap/memory_block.hpp
+++ b/arch/x86_64/include/arch/memory/heap/memory_block.hpp
@@ -1,6 +1,7 @@
 #ifndef TEACHOS_ARCH_X86_64_MEMORY_HEAP_MEMORY_BLOCK_HPP
 #define TEACHOS_ARCH_X86_64_MEMORY_HEAP_MEMORY_BLOCK_HPP
 
+#include <atomic>
 #include <cstdint>
 
 namespace teachos::arch::memory::heap
@@ -21,7 +22,7 @@ namespace teachos::arch::memory::heap
 
     std::size_t size;  ///< Amount of free memory this hole contains, has to always be atleast 16 bytes to hold the size
                        ///< variable and the pointer to the next hole.
-    memory_block * next;  ///< Optional pointer to the next free memory, holds nullptr if there is none.
+    std::atomic<memory_block *> next;  ///< Optional pointer to the next free memory, holds nullptr if there is none.
   };
 }  // namespace teachos::arch::memory::heap
 
diff --git a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
index f596f27..22b5757 100644
--- a/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
+++ b/arch/x86_64/src/memory/heap/linked_list_allocator.cpp
@@ -28,7 +28,7 @@ namespace teachos::arch::memory::heap
                                "[Linked List Allocator] Allocated memory cannot be smaller than 16 bytes");
 
     memory_block * previous = nullptr;
-    auto current = first;
+    auto current = first.load(std::memory_order::relaxed);
 
     while (current != nullptr)
     {
@@ -52,7 +52,7 @@ namespace teachos::arch::memory::heap
     auto const end_address = start_address + size;
 
     memory_block * previous = nullptr;
-    auto current = first;
+    auto current = first.load(std::memory_order::relaxed);
 
     while (current != nullptr)
     {
@@ -81,11 +81,11 @@ namespace teachos::arch::memory::heap
     // free block (nullptr). Therefore we have to overwrite the first block instead of overwriting its next value.
     if (previous_block == nullptr)
     {
-      first = new_block;
+      first.compare_exchange_weak(previous_block, new_block, std::memory_order::relaxed);
     }
     else
     {
-      previous_block->next = new_block;
+      previous_block->next.compare_exchange_weak(current_block, new_block, std::memory_order::relaxed);
     }
     clear_memory_block_header(current_block);
     return reinterpret_cast<void *>(start_address);