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2871df6f0d
As it turns out, Dr. POSIX doesn't require that post-mmap() changes to a file are reflected in the memory mappings. So we don't actually have to care about the file size changing (or the contents.) IIUC, as long as all the MAP_SHARED mappings that refer to the same inode are in sync, we're good. This means that VMObjects don't need resizing capabilities. I'm sure there are ways we can take advantage of this fact.
117 lines
3.3 KiB
C++
117 lines
3.3 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/FileSystem/Inode.h>
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#include <Kernel/VM/InodeVMObject.h>
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#include <Kernel/VM/MemoryManager.h>
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namespace Kernel {
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InodeVMObject::InodeVMObject(Inode& inode, size_t size)
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: VMObject(size)
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, m_inode(inode)
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, m_dirty_pages(page_count(), false)
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{
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}
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InodeVMObject::InodeVMObject(const InodeVMObject& other)
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: VMObject(other)
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, m_inode(other.m_inode)
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, m_dirty_pages(page_count(), false)
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{
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for (size_t i = 0; i < page_count(); ++i)
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m_dirty_pages.set(i, other.m_dirty_pages.get(i));
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}
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InodeVMObject::~InodeVMObject()
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{
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}
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size_t InodeVMObject::amount_clean() const
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{
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size_t count = 0;
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VERIFY(page_count() == m_dirty_pages.size());
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for (size_t i = 0; i < page_count(); ++i) {
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if (!m_dirty_pages.get(i) && m_physical_pages[i])
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++count;
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}
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return count * PAGE_SIZE;
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}
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size_t InodeVMObject::amount_dirty() const
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{
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size_t count = 0;
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for (size_t i = 0; i < m_dirty_pages.size(); ++i) {
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if (m_dirty_pages.get(i))
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++count;
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}
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return count * PAGE_SIZE;
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}
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int InodeVMObject::release_all_clean_pages()
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{
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LOCKER(m_paging_lock);
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return release_all_clean_pages_impl();
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}
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int InodeVMObject::release_all_clean_pages_impl()
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{
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int count = 0;
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InterruptDisabler disabler;
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for (size_t i = 0; i < page_count(); ++i) {
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if (!m_dirty_pages.get(i) && m_physical_pages[i]) {
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m_physical_pages[i] = nullptr;
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++count;
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}
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}
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for_each_region([](auto& region) {
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region.remap();
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});
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return count;
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}
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u32 InodeVMObject::writable_mappings() const
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{
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u32 count = 0;
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const_cast<InodeVMObject&>(*this).for_each_region([&](auto& region) {
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if (region.is_writable())
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++count;
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});
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return count;
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}
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u32 InodeVMObject::executable_mappings() const
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{
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u32 count = 0;
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const_cast<InodeVMObject&>(*this).for_each_region([&](auto& region) {
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if (region.is_executable())
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++count;
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});
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return count;
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}
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}
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