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https://github.com/LadybirdBrowser/ladybird.git
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3879e70447
This commit moves the allocation of the resources required for AnonymousVMObject from its constructors to its factory functions. We're making this change to expose the fallibility of the allocation.
90 lines
3.3 KiB
C++
90 lines
3.3 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/Memory/AllocationStrategy.h>
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#include <Kernel/Memory/MemoryManager.h>
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#include <Kernel/Memory/PageFaultResponse.h>
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#include <Kernel/Memory/VMObject.h>
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#include <Kernel/PhysicalAddress.h>
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namespace Kernel::Memory {
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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 ErrorOr<NonnullRefPtr<AnonymousVMObject>> try_create_with_size(size_t, AllocationStrategy);
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static ErrorOr<NonnullRefPtr<AnonymousVMObject>> try_create_for_physical_range(PhysicalAddress paddr, size_t size);
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static ErrorOr<NonnullRefPtr<AnonymousVMObject>> try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>>);
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static ErrorOr<NonnullRefPtr<AnonymousVMObject>> try_create_purgeable_with_size(size_t, AllocationStrategy);
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static ErrorOr<NonnullRefPtr<AnonymousVMObject>> try_create_physically_contiguous_with_size(size_t);
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virtual ErrorOr<NonnullRefPtr<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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ErrorOr<void> set_volatile(bool is_volatile, bool& was_purged);
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size_t purge();
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private:
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class SharedCommittedCowPages;
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explicit AnonymousVMObject(FixedArray<RefPtr<PhysicalPage>>&&, AllocationStrategy, Optional<CommittedPhysicalPageSet>);
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explicit AnonymousVMObject(PhysicalAddress, FixedArray<RefPtr<PhysicalPage>>&&);
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explicit AnonymousVMObject(FixedArray<RefPtr<PhysicalPage>>&&);
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explicit AnonymousVMObject(AnonymousVMObject const&, NonnullRefPtr<SharedCommittedCowPages>, FixedArray<RefPtr<PhysicalPage>>&&);
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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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Optional<CommittedPhysicalPageSet> m_unused_committed_pages;
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Bitmap m_cow_map;
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// AnonymousVMObject shares committed COW pages with cloned children (happens on fork)
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class SharedCommittedCowPages : public RefCounted<SharedCommittedCowPages> {
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AK_MAKE_NONCOPYABLE(SharedCommittedCowPages);
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public:
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SharedCommittedCowPages() = delete;
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explicit SharedCommittedCowPages(CommittedPhysicalPageSet&&);
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~SharedCommittedCowPages();
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[[nodiscard]] bool is_empty() const { return m_committed_pages.is_empty(); }
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[[nodiscard]] NonnullRefPtr<PhysicalPage> take_one();
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void uncommit_one();
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private:
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Spinlock m_lock;
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CommittedPhysicalPageSet m_committed_pages;
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};
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RefPtr<SharedCommittedCowPages> 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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