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https://github.com/RGBCube/serenity
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c1006a3689
By making sure the PhysicalPage instance is fully destructed the allocators will have a chance to reclaim the PhysicalPageEntry for free-list purposes. Just pass them the physical address of the page that was freed, which is enough to lookup the PhysicalPageEntry later.
61 lines
1.4 KiB
C++
61 lines
1.4 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/NonnullRefPtr.h>
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#include <Kernel/Assertions.h>
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#include <Kernel/Heap/SlabAllocator.h>
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#include <Kernel/PhysicalAddress.h>
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namespace Kernel {
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class PhysicalPage {
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friend class MemoryManager;
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friend class PageDirectory;
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friend class VMObject;
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public:
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PhysicalAddress paddr() const;
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void ref()
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{
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m_ref_count.fetch_add(1, AK::memory_order_acq_rel);
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}
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void unref()
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{
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if (m_ref_count.fetch_sub(1, AK::memory_order_acq_rel) == 1)
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free_this();
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}
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static NonnullRefPtr<PhysicalPage> create(PhysicalAddress, bool supervisor, bool may_return_to_freelist = true);
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u32 ref_count() const { return m_ref_count.load(AK::memory_order_consume); }
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bool is_shared_zero_page() const;
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bool is_lazy_committed_page() const;
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private:
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PhysicalPage(bool supervisor, bool may_return_to_freelist = true);
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~PhysicalPage() = default;
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void free_this();
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Atomic<u32> m_ref_count { 1 };
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bool m_may_return_to_freelist { true };
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bool m_supervisor { false };
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};
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struct PhysicalPageEntry {
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// This structure either holds a valid PhysicalPage
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// or a PhysicalAllocator's free list information!
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union {
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PhysicalPage physical_page;
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};
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};
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}
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