Kernel: Rename Kernel/VM/ to Kernel/Memory/

This directory isn't just about virtual memory, it's about all kinds
of memory management.

Kernel/Memory/VMObject.cpp

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/Memory/MemoryManager.h>
+#include <Kernel/Memory/VMObject.h>
+
+namespace Kernel {
+
+VMObject::VMObject(VMObject const& other)
+    : m_physical_pages(other.m_physical_pages)
+{
+    MM.register_vmobject(*this);
+}
+
+VMObject::VMObject(size_t size)
+    : m_physical_pages(ceil_div(size, static_cast<size_t>(PAGE_SIZE)))
+{
+    MM.register_vmobject(*this);
+}
+
+VMObject::~VMObject()
+{
+    {
+        ScopedSpinLock lock(m_on_deleted_lock);
+        for (auto& it : m_on_deleted)
+            it->vmobject_deleted(*this);
+        m_on_deleted.clear();
+    }
+
+    MM.unregister_vmobject(*this);
+    VERIFY(m_regions.is_empty());
+}
+
+}