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Kernel: Make PhysicalPage not movable and use atomic ref counting

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We should not be moving ref-counted objects.
This commit is contained in:
Tom 2020-08-21 21:49:50 -06:00 committed by Andreas Kling
parent 3320bb45d1
commit 08a569fbe0
5 changed files with 20 additions and 24 deletions
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8
Kernel/VM/MemoryManager.cpp
View file

@ -378,7 +378,7 @@ OwnPtr<Region> MemoryManager::allocate_kernel_region_with_vmobject(VMObject& vmo
return allocate_kernel_region_with_vmobject(range, vmobject, name, access, user_accessible, cacheable);
}
void MemoryManager::deallocate_user_physical_page(PhysicalPage&& page)
void MemoryManager::deallocate_user_physical_page(const PhysicalPage& page)
{
ScopedSpinLock lock(s_mm_lock);
for (auto& region : m_user_physical_regions) {
@ -387,7 +387,7 @@ void MemoryManager::deallocate_user_physical_page(PhysicalPage&& page)
continue;
}
region.return_page(move(page));
region.return_page(page);
--m_user_physical_pages_used;
return;
@ -448,7 +448,7 @@ RefPtr<PhysicalPage> MemoryManager::allocate_user_physical_page(ShouldZeroFill s
return page;
}
void MemoryManager::deallocate_supervisor_physical_page(PhysicalPage&& page)
void MemoryManager::deallocate_supervisor_physical_page(const PhysicalPage& page)
{
ScopedSpinLock lock(s_mm_lock);
for (auto& region : m_super_physical_regions) {
@ -457,7 +457,7 @@ void MemoryManager::deallocate_supervisor_physical_page(PhysicalPage&& page)
continue;
}
region.return_page(move(page));
region.return_page(page);
--m_super_physical_pages_used;
return;
}

4
Kernel/VM/MemoryManager.h
View file

@ -114,8 +114,8 @@ public:
RefPtr<PhysicalPage> allocate_user_physical_page(ShouldZeroFill = ShouldZeroFill::Yes);
RefPtr<PhysicalPage> allocate_supervisor_physical_page();
NonnullRefPtrVector<PhysicalPage> allocate_contiguous_supervisor_physical_pages(size_t size);
void deallocate_user_physical_page(PhysicalPage&&);
void deallocate_supervisor_physical_page(PhysicalPage&&);
void deallocate_user_physical_page(const PhysicalPage&);
void deallocate_supervisor_physical_page(const PhysicalPage&);
OwnPtr<Region> allocate_contiguous_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool cacheable = true);
OwnPtr<Region> allocate_kernel_region(size_t, const StringView& name, u8 access, bool user_accessible = false, bool should_commit = true, bool cacheable = true);

10
Kernel/VM/PhysicalPage.cpp
View file

@ -42,18 +42,14 @@ PhysicalPage::PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_retu
{
}
void PhysicalPage::return_to_freelist() &&
void PhysicalPage::return_to_freelist() const
{
ASSERT((paddr().get() & ~PAGE_MASK) == 0);
InterruptDisabler disabler;
m_ref_count = 1;
if (m_supervisor)
MM.deallocate_supervisor_physical_page(move(*this));
MM.deallocate_supervisor_physical_page(*this);
else
MM.deallocate_user_physical_page(move(*this));
MM.deallocate_user_physical_page(*this);
#ifdef MM_DEBUG
dbg() << "MM: P" << String::format("%x", m_paddr.get()) << " released to freelist";

18
Kernel/VM/PhysicalPage.h
View file

@ -39,29 +39,29 @@ class PhysicalPage {
friend class PageDirectory;
friend class VMObject;
MAKE_SLAB_ALLOCATED(PhysicalPage)
MAKE_SLAB_ALLOCATED(PhysicalPage);
AK_MAKE_NONMOVABLE(PhysicalPage);
public:
PhysicalAddress paddr() const { return m_paddr; }
void ref()
{
ASSERT(m_ref_count);
++m_ref_count;
m_ref_count.fetch_add(1, AK::memory_order_acq_rel);
}
void unref()
{
ASSERT(m_ref_count);
if (!--m_ref_count) {
if (m_ref_count.fetch_sub(1, AK::memory_order_acq_rel) == 1) {
if (m_may_return_to_freelist)
move(*this).return_to_freelist();
return_to_freelist();
delete this;
}
}
static NonnullRefPtr<PhysicalPage> create(PhysicalAddress, bool supervisor, bool may_return_to_freelist = true);
u32 ref_count() const { return m_ref_count; }
u32 ref_count() const { return m_ref_count.load(AK::memory_order_consume); }
bool is_shared_zero_page() const;
@ -69,9 +69,9 @@ private:
PhysicalPage(PhysicalAddress paddr, bool supervisor, bool may_return_to_freelist = true);
~PhysicalPage() {}
void return_to_freelist() &&;
void return_to_freelist() const;
u32 m_ref_count { 1 };
Atomic<u32> m_ref_count { 1 };
bool m_may_return_to_freelist { true };
bool m_supervisor { false };
PhysicalAddress m_paddr;

4
Kernel/VM/PhysicalRegion.h
View file

@ -49,12 +49,12 @@ public:
unsigned size() const { return m_pages; }
unsigned used() const { return m_used; }
unsigned free() const { return m_pages - m_used; }
bool contains(PhysicalPage& page) const { return page.paddr() >= m_lower && page.paddr() <= m_upper; }
bool contains(const PhysicalPage& page) const { return page.paddr() >= m_lower && page.paddr() <= m_upper; }
RefPtr<PhysicalPage> take_free_page(bool supervisor);
NonnullRefPtrVector<PhysicalPage> take_contiguous_free_pages(size_t count, bool supervisor);
void return_page_at(PhysicalAddress addr);
void return_page(PhysicalPage&& page) { return_page_at(page.paddr()); }
void return_page(const PhysicalPage& page) { return_page_at(page.paddr()); }
private:
unsigned find_contiguous_free_pages(size_t count);