diff --git a/ide/vs2017/mimalloc-override.vcxproj b/ide/vs2017/mimalloc-override.vcxproj
index 511c0fab..1fc70b33 100644
--- a/ide/vs2017/mimalloc-override.vcxproj
+++ b/ide/vs2017/mimalloc-override.vcxproj
@@ -231,6 +231,7 @@
     </ClCompile>
     <ClCompile Include="..\..\src\alloc-posix.c" />
     <ClCompile Include="..\..\src\alloc.c" />
+    <ClCompile Include="..\..\src\arena.c" />
     <ClCompile Include="..\..\src\heap.c" />
     <ClCompile Include="..\..\src\init.c" />
     <ClCompile Include="..\..\src\memory.c" />
diff --git a/ide/vs2017/mimalloc-override.vcxproj.filters b/ide/vs2017/mimalloc-override.vcxproj.filters
index 6ac0c0b5..75a8e032 100644
--- a/ide/vs2017/mimalloc-override.vcxproj.filters
+++ b/ide/vs2017/mimalloc-override.vcxproj.filters
@@ -70,5 +70,8 @@
     <ClCompile Include="..\..\src\alloc-posix.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\arena.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/ide/vs2017/mimalloc.vcxproj b/ide/vs2017/mimalloc.vcxproj
index 6147c349..484c4db8 100644
--- a/ide/vs2017/mimalloc.vcxproj
+++ b/ide/vs2017/mimalloc.vcxproj
@@ -217,6 +217,7 @@
     </ClCompile>
     <ClCompile Include="..\..\src\alloc-posix.c" />
     <ClCompile Include="..\..\src\alloc.c" />
+    <ClCompile Include="..\..\src\arena.c" />
     <ClCompile Include="..\..\src\heap.c" />
     <ClCompile Include="..\..\src\init.c" />
     <ClCompile Include="..\..\src\memory.c" />
diff --git a/ide/vs2017/mimalloc.vcxproj.filters b/ide/vs2017/mimalloc.vcxproj.filters
index a2b64314..598b8643 100644
--- a/ide/vs2017/mimalloc.vcxproj.filters
+++ b/ide/vs2017/mimalloc.vcxproj.filters
@@ -53,6 +53,9 @@
     <ClCompile Include="..\..\src\alloc-posix.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\arena.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="$(ProjectDir)..\..\include\mimalloc.h">
diff --git a/src/os.c b/src/os.c
index 8e1b3e91..4aa4abf3 100644
--- a/src/os.c
+++ b/src/os.c
@@ -794,6 +794,7 @@ and possibly associated with a specific NUMA node. (use `numa_node>=0`)
 static void* mi_os_alloc_huge_os_pagesx(size_t size, int numa_node)
 {
   mi_assert_internal(size%GiB == 0);
+  mi_win_enable_large_os_pages();
 
   #if defined(MEM_EXTENDED_PARAMETER_TYPE_BITS)
   DWORD flags = MEM_LARGE_PAGES | MEM_COMMIT | MEM_RESERVE;
@@ -812,7 +813,7 @@ static void* mi_os_alloc_huge_os_pagesx(size_t size, int numa_node)
     params[0].Pointer = &reqs;
     params[1].Type = 5; // == MemExtendedParameterAttributeFlags;
     params[1].ULong64 = MEM_EXTENDED_PARAMETER_NONPAGED_HUGE;
-    size_t param_count = 2;
+    ULONG param_count = 2;
     if (numa_node >= 0) {
       param_count++;
       params[2].Type = MemExtendedParameterNumaNode;
@@ -833,7 +834,7 @@ static void* mi_os_alloc_huge_os_pagesx(size_t size, int numa_node)
   if (pVirtualAlloc2 != NULL) {
     params[0].Type = MemExtendedParameterAddressRequirements;
     params[0].Pointer = &reqs;
-    size_t param_count = 1;
+    ULONG param_count = 1;
     if (numa_node >= 0) {
       param_count++;
       params[1].Type = MemExtendedParameterNumaNode;