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Kernel: If a VMObject is shared, broadcast page remappings

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If we remap pages (e.g. lazy allocation) inside a VMObject that is
shared among more than one region, broadcast it to any other region
that may be mapping the same page.
This commit is contained in:
Tom 2021-01-02 12:03:14 -07:00 • committed by Andreas Kling
parent e3190bd144
commit c630669304
5 changed files with 117 additions and 18 deletions
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50
Kernel/VM/Region.h
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@ -122,6 +122,49 @@ public:
return vaddr().offset(page_index * PAGE_SIZE);
}
bool translate_vmobject_page(size_t& index) const
{
auto first_index = first_page_index();
if (index < first_index) {
index = first_index;
return false;
}
index -= first_index;
auto total_page_count = this->page_count();
if (index >= total_page_count) {
index = first_index + total_page_count - 1;
return false;
}
return true;
}
bool translate_vmobject_page_range(size_t& index, size_t& page_count) const
{
auto first_index = first_page_index();
if (index < first_index) {
auto delta = first_index - index;
index = first_index;
if (delta >= page_count) {
page_count = 0;
return false;
}
page_count -= delta;
}
index -= first_index;
auto total_page_count = this->page_count();
if (index + page_count > total_page_count) {
page_count = total_page_count - index;
if (page_count == 0)
return false;
}
return true;
}
ALWAYS_INLINE size_t translate_to_vmobject_page(size_t page_index) const
{
return first_page_index() + page_index;
}
size_t first_page_index() const
{
return m_offset_in_vmobject / PAGE_SIZE;
@ -186,7 +229,7 @@ public:
void set_inherit_mode(InheritMode inherit_mode) { m_inherit_mode = inherit_mode; }
bool remap_page_range(size_t page_index, size_t page_count);
bool remap_vmobject_page_range(size_t page_index, size_t page_count);
bool is_volatile(VirtualAddress vaddr, size_t size) const;
enum class SetVolatileError {
@ -199,6 +242,8 @@ public:
RefPtr<Process> get_owner();
private:
bool do_remap_vmobject_page_range(size_t page_index, size_t page_count);
void set_access_bit(Access access, bool b)
{
if (b)
@ -207,7 +252,8 @@ private:
m_access &= ~access;
}
bool remap_page(size_t index, bool with_flush = true);
bool do_remap_vmobject_page(size_t index, bool with_flush = true);
bool remap_vmobject_page(size_t index, bool with_flush = true);
PageFaultResponse handle_cow_fault(size_t page_index);
PageFaultResponse handle_inode_fault(size_t page_index);