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https://github.com/RGBCube/serenity
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6a537ceef1
We don't need an entirely separate VMObject subclass to influence the location of the physical pages. Instead, we simply allocate enough physically contiguous memory first, and then pass it to the AnonymousVMObject constructor that takes a span of physical pages.
85 lines
2.7 KiB
C++
85 lines
2.7 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 <Kernel/PhysicalAddress.h>
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#include <Kernel/VM/AllocationStrategy.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PageFaultResponse.h>
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#include <Kernel/VM/VMObject.h>
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namespace Kernel {
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class CommittedCowPages : public RefCounted<CommittedCowPages> {
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AK_MAKE_NONCOPYABLE(CommittedCowPages);
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public:
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CommittedCowPages() = delete;
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CommittedCowPages(size_t);
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~CommittedCowPages();
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NonnullRefPtr<PhysicalPage> allocate_one();
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bool return_one();
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private:
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size_t m_committed_pages;
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};
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class AnonymousVMObject final : public VMObject {
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public:
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virtual ~AnonymousVMObject() override;
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static RefPtr<AnonymousVMObject> try_create_with_size(size_t, AllocationStrategy);
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static RefPtr<AnonymousVMObject> try_create_for_physical_range(PhysicalAddress paddr, size_t size);
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static RefPtr<AnonymousVMObject> try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>>);
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static RefPtr<AnonymousVMObject> try_create_purgeable_with_size(size_t, AllocationStrategy);
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static RefPtr<AnonymousVMObject> try_create_physically_contiguous_with_size(size_t);
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virtual RefPtr<VMObject> try_clone() override;
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[[nodiscard]] NonnullRefPtr<PhysicalPage> allocate_committed_page(Badge<Region>);
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PageFaultResponse handle_cow_fault(size_t, VirtualAddress);
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size_t cow_pages() const;
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bool should_cow(size_t page_index, bool) const;
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void set_should_cow(size_t page_index, bool);
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bool is_purgeable() const { return m_purgeable; }
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bool is_volatile() const { return m_volatile; }
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KResult set_volatile(bool is_volatile, bool& was_purged);
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size_t purge();
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private:
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explicit AnonymousVMObject(size_t, AllocationStrategy);
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explicit AnonymousVMObject(PhysicalAddress, size_t);
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explicit AnonymousVMObject(Span<NonnullRefPtr<PhysicalPage>>);
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explicit AnonymousVMObject(AnonymousVMObject const&);
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virtual StringView class_name() const override { return "AnonymousVMObject"sv; }
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AnonymousVMObject& operator=(AnonymousVMObject const&) = delete;
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AnonymousVMObject& operator=(AnonymousVMObject&&) = delete;
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AnonymousVMObject(AnonymousVMObject&&) = delete;
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virtual bool is_anonymous() const override { return true; }
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Bitmap& ensure_cow_map();
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void ensure_or_reset_cow_map();
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size_t m_unused_committed_pages { 0 };
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Bitmap m_cow_map;
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// We share a pool of committed cow-pages with clones
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RefPtr<CommittedCowPages> m_shared_committed_cow_pages;
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bool m_purgeable { false };
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bool m_volatile { false };
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bool m_was_purged { false };
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};
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}
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