ladybird/Kernel/VM/VMObject.h
Andreas Kling 0d963fd641 Kernel: Remove unnecessary counting of VMObject-attached Regions
VMObject already has an IntrusiveList of all the Regions that map it.
We were keeping a counter in addition to this, and only using it in
a single place to avoid iterating over the list in case it only had
1 entry.

Simplify VMObject by removing this counter and always iterating the
list even if there's only 1 entry. :^)
2021-07-25 17:28:06 +02:00

122 lines
3.2 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/FixedArray.h>
#include <AK/HashTable.h>
#include <AK/IntrusiveList.h>
#include <AK/RefCounted.h>
#include <AK/RefPtr.h>
#include <AK/Vector.h>
#include <AK/Weakable.h>
#include <Kernel/Forward.h>
#include <Kernel/Mutex.h>
#include <Kernel/VM/Region.h>
namespace Kernel {
class VMObjectDeletedHandler {
public:
virtual ~VMObjectDeletedHandler() = default;
virtual void vmobject_deleted(VMObject&) = 0;
};
class VMObject : public RefCounted<VMObject>
, public Weakable<VMObject> {
friend class MemoryManager;
friend class Region;
public:
virtual ~VMObject();
virtual RefPtr<VMObject> try_clone() = 0;
virtual bool is_anonymous() const { return false; }
virtual bool is_inode() const { return false; }
virtual bool is_shared_inode() const { return false; }
virtual bool is_private_inode() const { return false; }
virtual bool is_contiguous() const { return false; }
size_t page_count() const { return m_physical_pages.size(); }
Span<RefPtr<PhysicalPage> const> physical_pages() const { return m_physical_pages.span(); }
Span<RefPtr<PhysicalPage>> physical_pages() { return m_physical_pages.span(); }
size_t size() const { return m_physical_pages.size() * PAGE_SIZE; }
virtual StringView class_name() const = 0;
ALWAYS_INLINE void add_region(Region& region)
{
ScopedSpinLock locker(m_lock);
m_regions.append(region);
}
ALWAYS_INLINE void remove_region(Region& region)
{
ScopedSpinLock locker(m_lock);
m_regions.remove(region);
}
void register_on_deleted_handler(VMObjectDeletedHandler& handler)
{
ScopedSpinLock locker(m_on_deleted_lock);
m_on_deleted.set(&handler);
}
void unregister_on_deleted_handler(VMObjectDeletedHandler& handler)
{
ScopedSpinLock locker(m_on_deleted_lock);
m_on_deleted.remove(&handler);
}
protected:
explicit VMObject(size_t);
explicit VMObject(VMObject const&);
template<typename Callback>
void for_each_region(Callback);
IntrusiveListNode<VMObject> m_list_node;
FixedArray<RefPtr<PhysicalPage>> m_physical_pages;
mutable RecursiveSpinLock m_lock;
private:
VMObject& operator=(VMObject const&) = delete;
VMObject& operator=(VMObject&&) = delete;
VMObject(VMObject&&) = delete;
HashTable<VMObjectDeletedHandler*> m_on_deleted;
SpinLock<u8> m_on_deleted_lock;
Region::ListInVMObject m_regions;
public:
using List = IntrusiveList<VMObject, RawPtr<VMObject>, &VMObject::m_list_node>;
};
template<typename Callback>
inline void VMObject::for_each_region(Callback callback)
{
ScopedSpinLock lock(m_lock);
for (auto& region : m_regions) {
callback(region);
}
}
inline PhysicalPage const* Region::physical_page(size_t index) const
{
VERIFY(index < page_count());
return vmobject().physical_pages()[first_page_index() + index];
}
inline RefPtr<PhysicalPage>& Region::physical_page_slot(size_t index)
{
VERIFY(index < page_count());
return vmobject().physical_pages()[first_page_index() + index];
}
}