system/PageAllocator: move PAGE_SIZE and AlignToPageSize() to PageSize.hxx

Author: MaxKellermann

src/memory/SlicePool.cxx

@@ -7,6 +7,7 @@
 #include "Checker.hxx"
 #include "AllocatorStats.hxx"
 #include "system/PageAllocator.hxx"
+#include "system/PageSize.hxx"
 #include "system/HugePage.hxx"
 #include "system/VmaName.hxx"
 #include "util/DivideRoundUp.hxx"

src/system/LargeAllocation.cxx

@@ -4,6 +4,7 @@
 
 #include "LargeAllocation.hxx"
 #include "PageAllocator.hxx"
+#include "PageSize.hxx"
 
 #include <new>
 

src/system/PageAllocator.hxx

@@ -11,17 +11,6 @@
 
 #include <sys/mman.h>
 
-static constexpr std::size_t PAGE_SIZE = 4096;
-
-/**
- * Round up the parameter, make it page-aligned.
- */
-static constexpr std::size_t
-AlignToPageSize(std::size_t size) noexcept
-{
-	return RoundUpToPowerOfTwo(size, PAGE_SIZE);
-}
-
 /**
  * Allocate pages from the kernel
  *

src/system/PageSize.hxx

@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: BSD-2-Clause
+// Copyright CM4all GmbH
+// author: Max Kellermann <max.kellermann@ionos.com>
+
+#pragma once
+
+#include "util/RoundPowerOfTwo.hxx"
+
+#include <cstddef>
+
+#include <sys/mman.h>
+
+static constexpr std::size_t PAGE_SIZE = 4096;
+
+/**
+ * Round up the parameter, make it page-aligned.
+ */
+static constexpr std::size_t
+AlignToPageSize(std::size_t size) noexcept
+{
+	return RoundUpToPowerOfTwo(size, PAGE_SIZE);
+}