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Replace zones with individually tracked physical pages.

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It's just a simple struct { ref_count, paddr }.
This will allow me to implement lazy zeroing and COW pages.
This commit is contained in:
Andreas Kling 2018-11-05 10:23:00 +01:00
parent b5c5286ee1
commit 72cdc62155
10 changed files with 161 additions and 127 deletions
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64
Kernel/MemoryManager.h
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@ -17,34 +17,50 @@ enum class PageFaultResponse {
Continue,
};
struct PageDirectory {
dword entries[1024];
PhysicalAddress physical_addresses[1024];
};
struct Zone : public Retainable<Zone> {
friend ByteBuffer procfs$mm();
class PhysicalPage {
friend class MemoryManager;
public:
~Zone();
size_t size() const { return m_pages.size() * PAGE_SIZE; }
~PhysicalPage() { }
PhysicalAddress paddr() const { return m_paddr; }
const Vector<PhysicalAddress>& pages() const { return m_pages; }
void retain()
{
ASSERT(m_retain_count);
++m_retain_count;
}
void release()
{
ASSERT(m_retain_count);
if (!--m_retain_count)
return_to_freelist();
}
private:
friend class MemoryManager;
explicit Zone(Vector<PhysicalAddress>&&);
PhysicalPage(PhysicalAddress paddr)
: m_paddr(paddr)
{
}
Vector<PhysicalAddress> m_pages;
void return_to_freelist();
unsigned m_retain_count { 1 };
PhysicalAddress m_paddr;
};
struct PageDirectory {
dword entries[1024];
RetainPtr<PhysicalPage> physical_pages[1024];
};
struct Region : public Retainable<Region> {
Region(LinearAddress, size_t, RetainPtr<Zone>&&, String&&, bool r, bool w);
Region(LinearAddress, size_t, Vector<RetainPtr<PhysicalPage>>, String&&, bool r, bool w);
~Region();
RetainPtr<Region> clone();
LinearAddress linearAddress;
size_t size { 0 };
RetainPtr<Zone> zone;
Vector<RetainPtr<PhysicalPage>> physical_pages;
String name;
bool is_readable { true };
bool is_writable { true };
@ -54,6 +70,7 @@ struct Region : public Retainable<Region> {
class MemoryManager {
AK_MAKE_ETERNAL
friend class PhysicalPage;
friend ByteBuffer procfs$mm();
public:
static MemoryManager& the() PURE;
@ -64,14 +81,9 @@ public:
PageFaultResponse handlePageFault(const PageFault&);
RetainPtr<Zone> createZone(size_t);
bool mapRegion(Process&, Region&);
bool unmapRegion(Process&, Region&);
void registerZone(Zone&);
void unregisterZone(Zone&);
void populate_page_directory(PageDirectory&);
void release_page_directory(PageDirectory&);
@ -84,6 +96,8 @@ public:
bool validate_user_read(const Process&, LinearAddress) const;
bool validate_user_write(const Process&, LinearAddress) const;
Vector<RetainPtr<PhysicalPage>> allocate_physical_pages(size_t count);
private:
MemoryManager();
~MemoryManager();
@ -96,16 +110,14 @@ private:
void flushEntireTLB();
void flushTLB(LinearAddress);
PhysicalAddress allocate_page_table();
void deallocate_page_table(PhysicalAddress);
RetainPtr<PhysicalPage> allocate_page_table(PageDirectory&, unsigned index);
void deallocate_page_table(PageDirectory&, unsigned index);
void protectMap(LinearAddress, size_t length);
void create_identity_mapping(LinearAddress, size_t length);
void remove_identity_mapping(LinearAddress, size_t);
Vector<PhysicalAddress> allocatePhysicalPages(size_t count);
struct PageDirectoryEntry {
explicit PageDirectoryEntry(dword* pde) : m_pde(pde) { }
@ -192,9 +204,7 @@ private:
LinearAddress m_next_laddr;
HashTable<Zone*> m_zones;
Vector<PhysicalAddress> m_freePages;
Vector<RetainPtr<PhysicalPage>> m_free_physical_pages;
};
struct KernelPagingScope {