mirror of
https://github.com/SerenityOS/serenity.git
synced 2025-01-23 09:51:57 -05:00
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.
94 lines
2.3 KiB
C++
94 lines
2.3 KiB
C++
/*
|
|
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <Kernel/FileSystem/Inode.h>
|
|
#include <Kernel/Memory/InodeVMObject.h>
|
|
|
|
namespace Kernel::Memory {
|
|
|
|
InodeVMObject::InodeVMObject(Inode& inode, FixedArray<RefPtr<PhysicalRAMPage>>&& new_physical_pages, Bitmap dirty_pages)
|
|
: VMObject(move(new_physical_pages))
|
|
, m_inode(inode)
|
|
, m_dirty_pages(move(dirty_pages))
|
|
{
|
|
}
|
|
|
|
InodeVMObject::InodeVMObject(InodeVMObject const& other, FixedArray<RefPtr<PhysicalRAMPage>>&& new_physical_pages, Bitmap dirty_pages)
|
|
: VMObject(move(new_physical_pages))
|
|
, m_inode(other.m_inode)
|
|
, m_dirty_pages(move(dirty_pages))
|
|
{
|
|
for (size_t i = 0; i < page_count(); ++i)
|
|
m_dirty_pages.set(i, other.m_dirty_pages.get(i));
|
|
}
|
|
|
|
InodeVMObject::~InodeVMObject() = default;
|
|
|
|
size_t InodeVMObject::amount_clean() const
|
|
{
|
|
size_t count = 0;
|
|
VERIFY(page_count() == m_dirty_pages.size());
|
|
for (size_t i = 0; i < page_count(); ++i) {
|
|
if (!m_dirty_pages.get(i) && m_physical_pages[i])
|
|
++count;
|
|
}
|
|
return count * PAGE_SIZE;
|
|
}
|
|
|
|
size_t InodeVMObject::amount_dirty() const
|
|
{
|
|
size_t count = 0;
|
|
for (size_t i = 0; i < m_dirty_pages.size(); ++i) {
|
|
if (m_dirty_pages.get(i))
|
|
++count;
|
|
}
|
|
return count * PAGE_SIZE;
|
|
}
|
|
|
|
bool InodeVMObject::is_page_dirty(size_t page_index) const
|
|
{
|
|
VERIFY(m_lock.is_locked());
|
|
return m_dirty_pages.get(page_index);
|
|
}
|
|
|
|
void InodeVMObject::set_page_dirty(size_t page_index, bool is_dirty)
|
|
{
|
|
VERIFY(m_lock.is_locked());
|
|
m_dirty_pages.set(page_index, is_dirty);
|
|
}
|
|
|
|
int InodeVMObject::release_all_clean_pages()
|
|
{
|
|
return try_release_clean_pages(page_count());
|
|
}
|
|
|
|
int InodeVMObject::try_release_clean_pages(int page_amount)
|
|
{
|
|
SpinlockLocker locker(m_lock);
|
|
|
|
int count = 0;
|
|
for (size_t i = 0; i < page_count() && count < page_amount; ++i) {
|
|
if (!m_dirty_pages.get(i) && m_physical_pages[i]) {
|
|
m_physical_pages[i] = nullptr;
|
|
++count;
|
|
}
|
|
}
|
|
if (count)
|
|
remap_regions();
|
|
return count;
|
|
}
|
|
|
|
u32 InodeVMObject::writable_mappings() const
|
|
{
|
|
u32 count = 0;
|
|
const_cast<InodeVMObject&>(*this).for_each_region([&](auto& region) {
|
|
if (region.is_writable())
|
|
++count;
|
|
});
|
|
return count;
|
|
}
|
|
|
|
}
|