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https://github.com/SerenityOS/serenity
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3e9b269bcd
InodeVMObjects now track dirty and clean pages. This tracking of dirty and clean pages is used by the msync and purge syscalls. dirty page tracking works using the following rules: * when a new InodeVMObject is made, all pages are marked clean. * writes to clean InodeVMObject pages will cause a page fault, the fault handler will mark the page as dirty. * writes to dirty InodeVMObject pages do not cause page faults. * if msync is called, only dirty pages are flushed to storage (and marked clean). * if purge syscall is called, only clean pages are discarded.
48 lines
1.2 KiB
C++
48 lines
1.2 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/Bitmap.h>
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#include <Kernel/Memory/VMObject.h>
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#include <Kernel/UnixTypes.h>
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namespace Kernel::Memory {
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class InodeVMObject : public VMObject {
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public:
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virtual ~InodeVMObject() override;
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Inode& inode() { return *m_inode; }
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Inode const& inode() const { return *m_inode; }
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size_t amount_dirty() const;
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size_t amount_clean() const;
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bool is_page_dirty(size_t page_index) const;
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void set_page_dirty(size_t page_index, bool is_dirty);
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int release_all_clean_pages();
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int try_release_clean_pages(int page_amount);
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u32 writable_mappings() const;
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protected:
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explicit InodeVMObject(Inode&, FixedArray<RefPtr<PhysicalRAMPage>>&&, Bitmap dirty_pages);
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explicit InodeVMObject(InodeVMObject const&, FixedArray<RefPtr<PhysicalRAMPage>>&&, Bitmap dirty_pages);
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InodeVMObject& operator=(InodeVMObject const&) = delete;
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InodeVMObject& operator=(InodeVMObject&&) = delete;
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InodeVMObject(InodeVMObject&&) = delete;
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virtual bool is_inode() const final { return true; }
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NonnullRefPtr<Inode> const m_inode;
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Bitmap m_dirty_pages;
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};
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}
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