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Kernel: Stop trying to keep InodeVMObject in sync with disk changes

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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.
This commit is contained in:
Andreas Kling 2021-03-04 15:08:37 +01:00
parent 9547846a18
commit 2871df6f0d
6 changed files with 0 additions and 69 deletions
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32
Kernel/VM/InodeVMObject.cpp
View file

@ -71,38 +71,6 @@ size_t InodeVMObject::amount_dirty() const
return count * PAGE_SIZE;
}
void InodeVMObject::inode_size_changed(Badge<Inode>, size_t old_size, size_t new_size)
{
dbgln("VMObject::inode_size_changed: ({}:{}) {} -> {}", m_inode->fsid(), m_inode->index(), old_size, new_size);
InterruptDisabler disabler;
auto new_page_count = page_round_up(new_size) / PAGE_SIZE;
m_physical_pages.resize(new_page_count);
m_dirty_pages.grow(new_page_count, false);
// FIXME: Consolidate with inode_contents_changed() so we only do a single walk.
for_each_region([](auto& region) {
region.remap();
});
}
void InodeVMObject::inode_contents_changed(Badge<Inode>, off_t offset, [[maybe_unused]] ssize_t size, [[maybe_unused]] const UserOrKernelBuffer& data)
{
InterruptDisabler disabler;
VERIFY(offset >= 0);
// FIXME: Only invalidate the parts that actually changed.
for (auto& physical_page : m_physical_pages)
physical_page = nullptr;
// FIXME: Consolidate with inode_size_changed() so we only do a single walk.
for_each_region([](auto& region) {
region.remap();
});
}
int InodeVMObject::release_all_clean_pages()
{
LOCKER(m_paging_lock);