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a6a439243f
This step would ideally not have been necessary (increases amount of refactoring and templates necessary, which in turn increases build times), but it gives us a couple of nice properties: - SpinlockProtected inside Singleton (a very common combination) can now obtain any lock rank just via the template parameter. It was not previously possible to do this with SingletonInstanceCreator magic. - SpinlockProtected's lock rank is now mandatory; this is the majority of cases and allows us to see where we're still missing proper ranks. - The type already informs us what lock rank a lock has, which aids code readability and (possibly, if gdb cooperates) lock mismatch debugging. - The rank of a lock can no longer be dynamic, which is not something we wanted in the first place (or made use of). Locks randomly changing their rank sounds like a disaster waiting to happen. - In some places, we might be able to statically check that locks are taken in the right order (with the right lock rank checking implementation) as rank information is fully statically known. This refactoring even more exposes the fact that Mutex has no lock rank capabilites, which is not fixed here.
93 lines
3.6 KiB
C++
93 lines
3.6 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<NonnullLockRefPtr<AnonymousVMObject>> try_create_with_size(size_t, AllocationStrategy);
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static ErrorOr<NonnullLockRefPtr<AnonymousVMObject>> try_create_for_physical_range(PhysicalAddress paddr, size_t size);
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static ErrorOr<NonnullLockRefPtr<AnonymousVMObject>> try_create_with_physical_pages(Span<NonnullRefPtr<PhysicalPage>>);
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static ErrorOr<NonnullLockRefPtr<AnonymousVMObject>> try_create_purgeable_with_size(size_t, AllocationStrategy);
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static ErrorOr<NonnullLockRefPtr<AnonymousVMObject>> try_create_physically_contiguous_with_size(size_t);
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virtual ErrorOr<NonnullLockRefPtr<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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ErrorOr<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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static ErrorOr<NonnullLockRefPtr<AnonymousVMObject>> try_create_with_shared_cow(AnonymousVMObject const&, NonnullLockRefPtr<SharedCommittedCowPages>, FixedArray<RefPtr<PhysicalPage>>&&);
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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(LockWeakPtr<AnonymousVMObject>, NonnullLockRefPtr<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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ErrorOr<void> ensure_cow_map();
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ErrorOr<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 final : public AtomicRefCounted<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<LockRank::None> m_lock {};
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CommittedPhysicalPageSet m_committed_pages;
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};
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LockWeakPtr<AnonymousVMObject> m_cow_parent;
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LockRefPtr<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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