X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;ds=sidebyside;f=Kernel%2Farch%2Fx86_64%2Fmm_phys.c;h=c2c215b3b99603d96146a1044d4451cedfbc2919;hb=e31829ecc2b8ae2338745f4ed393748704a81531;hp=e2c2cf6ecabcc39f56a353e419de195b18518d2f;hpb=2af4884a872632edd582f632c65506af68fb0efa;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86_64/mm_phys.c b/Kernel/arch/x86_64/mm_phys.c
index e2c2cf6e..c2c215b3 100644
--- a/Kernel/arch/x86_64/mm_phys.c
+++ b/Kernel/arch/x86_64/mm_phys.c
@@ -3,10 +3,13 @@
  * 
  * Physical Memory Manager
  */
+#define DEBUG	0
 #include <acess.h>
 #include <mboot.h>
 #include <mm_virt.h>
 
+#define TRACE_REF	0
+
 enum eMMPhys_Ranges
 {
 	MM_PHYS_16BIT,	// Does anything need this?
@@ -18,23 +21,32 @@ enum eMMPhys_Ranges
 };
 
 // === IMPORTS ===
-extern void	gKernelBase;
-extern void	gKernelEnd;
+extern char	gKernelBase[];
+extern char	gKernelEnd[];
 
 // === PROTOTYPES ===
 void	MM_InitPhys_Multiboot(tMBoot_Info *MBoot);
-tPAddr	MM_AllocPhysRange(int Num, int Bits);
-tPAddr	MM_AllocPhys(void);
-void	MM_RefPhys(tPAddr PAddr);
-void	MM_DerefPhys(tPAddr PAddr);
+//tPAddr	MM_AllocPhysRange(int Num, int Bits);
+//tPAddr	MM_AllocPhys(void);
+//void	MM_RefPhys(tPAddr PAddr);
+//void	MM_DerefPhys(tPAddr PAddr);
  int	MM_int_GetRangeID( tPAddr Addr );
 
+// === MACROS ===
+#define PAGE_ALLOC_TEST(__page) 	(gaMainBitmap[(__page)>>6] & (1ULL << ((__page)&63)))
+#define PAGE_ALLOC_SET(__page)  	do{gaMainBitmap[(__page)>>6] |= (1ULL << ((__page)&63));}while(0)
+#define PAGE_ALLOC_CLEAR(__page)	do{gaMainBitmap[(__page)>>6] &= ~(1ULL << ((__page)&63));}while(0)
+//#define PAGE_MULTIREF_TEST(__page)	(gaMultiBitmap[(__page)>>6] & (1ULL << ((__page)&63)))
+//#define PAGE_MULTIREF_SET(__page)	do{gaMultiBitmap[(__page)>>6] |= 1ULL << ((__page)&63);}while(0)
+//#define PAGE_MULTIREF_CLEAR(__page)	do{gaMultiBitmap[(__page)>>6] &= ~(1ULL << ((__page)&63));}while(0)
+
 // === GLOBALS ===
-tSpinlock	glPhysicalPages;
-Uint64	*gaSuperBitmap;	// 1 bit = 64 Pages, 16 MiB Per Word
-Uint64	*gaMainBitmap;	// 1 bit = 1 Page, 256 KiB per Word
-Uint64	*gaMultiBitmap;	// Each bit means that the page is being used multiple times
+tMutex	glPhysicalPages;
+Uint64	*gaSuperBitmap = (void*)MM_PAGE_SUPBMP;	// 1 bit = 64 Pages, 16 MiB per Word
+Uint64	*gaMainBitmap = (void*)MM_PAGE_BITMAP;	// 1 bit = 1 Page, 256 KiB per Word
+Uint64	*gaMultiBitmap = (void*)MM_PAGE_DBLBMP;	// Each bit means that the page is being used multiple times
 Uint32	*gaiPageReferences = (void*)MM_PAGE_COUNTS;	// Reference Counts
+void	**gapPageNodes = (void*)MM_PAGE_NODES;	// Reference Counts
 tPAddr	giFirstFreePage;	// First possibly free page
 Uint64	giPhysRangeFree[NUM_MM_PHYS_RANGES];	// Number of free pages in each range
 Uint64	giPhysRangeFirst[NUM_MM_PHYS_RANGES];	// First free page in each range
@@ -61,18 +73,18 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 	tVAddr	vaddr;
 	tPAddr	paddr, firstFreePage;
 	
-	Log("MM_InitPhys_Multiboot: (MBoot=%p)", MBoot);
+	ENTER("pMBoot=%p", MBoot);
 	
 	// Scan the physical memory map
 	// Looking for the top of physical memory
 	mmapStart = (void *)( KERNEL_BASE | MBoot->MMapAddr );
-	Log(" MM_InitPhys_Multiboot: mmapStart = %p", mmapStart);
+	LOG("mmapStart = %p", mmapStart);
 	ent = mmapStart;
 	while( (Uint)ent < (Uint)mmapStart + MBoot->MMapLength )
 	{
 		// Adjust for the size of the entry
 		ent->Size += 4;
-		Log(" MM_InitPhys_Multiboot: ent={Type:%i,Base:0x%x,Length:%x",
+		LOG("ent={Type:%i,Base:0x%x,Length:%x",
 			ent->Type, ent->Base, ent->Length);
 		
 		// If entry is RAM and is above `maxAddr`, change `maxAddr`
@@ -92,7 +104,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 		// Goodie, goodie gumdrops
 		giMaxPhysPage = maxAddr >> 12;
 	}
-	Log(" MM_InitPhys_Multiboot: giMaxPhysPage = 0x%x", giMaxPhysPage);
+	LOG("giMaxPhysPage = 0x%x", giMaxPhysPage);
 	
 	// Find a contigous section of memory to hold it in
 	// - Starting from the end of the kernel
@@ -100,8 +112,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 	superPages = ((giMaxPhysPage+64*8-1)/(64*8) + 0xFFF) >> 12;
 	numPages = (giMaxPhysPage + 7) / 8;
 	numPages = (numPages + 0xFFF) >> 12;
-	Log(" MM_InitPhys_Multiboot: numPages = %i, superPages = %i",
-		numPages, superPages);
+	LOG("numPages = %i, superPages = %i", numPages, superPages);
 	if(maxAddr == 0)
 	{
 		 int	todo = numPages*2 + superPages;
@@ -153,7 +164,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 			if( ent->Base + ent->Size < (tPAddr)&gKernelBase )
 				continue;
 			
-			Log(" MM_InitPhys_Multiboot: %x <= %x && %x > %x",
+			LOG("%x <= %x && %x > %x",
 				ent->Base, (tPAddr)&gKernelBase,
 				ent->Base + ent->Size, (tPAddr)&gKernelEnd - KERNEL_BASE
 				);
@@ -172,7 +183,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 				paddr = ent->Base;
 			}
 			
-			Log(" MM_InitPhys_Multiboot: paddr=0x%x, avail=%i", paddr, avail);
+			Log("MM_InitPhys_Multiboot: paddr=0x%x, avail=0x%x pg", paddr, avail);
 			
 			// Map
 			while( todo && avail --)
@@ -206,14 +217,15 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 	// Save the current value of paddr to simplify the allocation later
 	firstFreePage = paddr;
 	
-	Log(" MM_InitPhys_Multiboot: Clearing multi bitmap");
+	LOG("Clearing multi bitmap");
 	// Fill the bitmaps
-	memset(gaMultiBitmap, 0, numPages<<12);
+	memset(gaMultiBitmap, 0, (numPages<<12)/8);
 	// - initialise to one, then clear the avaliable areas
-	memset(gaMainBitmap, -1, numPages<<12);
-	Log(" MM_InitPhys_Multiboot: Setting main bitmap");
+	memset(gaMainBitmap, -1, (numPages<<12)/8);
+	memset(gaSuperBitmap, -1, (numPages<<12)/(8*64));
+	LOG("Setting main bitmap");
 	// - Clear all Type=1 areas
-	Log(" MM_InitPhys_Multiboot: Clearing valid regions");
+	LOG("Clearing valid regions");
 	for(
 		ent = mmapStart;
 		(Uint)ent < (Uint)mmapStart + MBoot->MMapLength;
@@ -228,14 +240,14 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 		size = ent->Size >> 12;
 		
 		if(base & 63) {
-			Uint64	val = -1 << (base & 63);
+			Uint64	val = -1LL << (base & 63);
 			gaMainBitmap[base / 64] &= ~val;
 			size -= (base & 63);
 			base += 64 - (base & 63);
 		}
 		memset( &gaMainBitmap[base / 64], 0, size/8 );
 		if( size & 7 ) {
-			Uint64	val = -1 << (size & 7);
+			Uint64	val = -1LL << (size & 7);
 			val <<= (size/8)&7;
 			gaMainBitmap[base / 64] &= ~val;
 		}
@@ -246,10 +258,10 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 		size = (size + (base & 63) + 63) >> 6;
 		base = base >> 6;
 		if(base & 63) {
-			Uint64	val = -1 << (base & 63);
+			Uint64	val = -1LL << (base & 63);
 			gaSuperBitmap[base / 64] &= ~val;
-			size -= (base & 63);
-			base += 64 - (base & 63);
+//			size -= (base & 63);
+//			base += 64 - (base & 63);
 		}
 	}
 	
@@ -258,7 +270,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 	size = firstFreePage >> 12;
 	memset( &gaMainBitmap[base / 64], -1, size/8 );
 	if( size & 7 ) {
-		Uint64	val = -1 << (size & 7);
+		Uint64	val = -1LL << (size & 7);
 		val <<= (size/8)&7;
 		gaMainBitmap[base / 64] |= val;
 	}
@@ -268,16 +280,16 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 		if(gaiStaticAllocPages[i] != 0)
 			continue;
 		gaMainBitmap[ gaiStaticAllocPages[i] >> (12+6) ]
-			&= ~(1 << ((gaiStaticAllocPages[i]>>12)&63));
+			&= ~(1LL << ((gaiStaticAllocPages[i]>>12)&63));
 	}
 	
 	// Fill the super bitmap
-	Log(" MM_InitPhys_Multiboot: Filling super bitmap");
+	LOG("Filling super bitmap");
 	memset(gaSuperBitmap, 0, superPages<<12);
 	for( base = 0; base < (size+63)/64; base ++)
 	{
-		if( gaMainBitmap[ base ] == -1 )
-			gaSuperBitmap[ base/64 ] |= 1 << (base&63);
+		if( gaMainBitmap[ base ] + 1 == 0 )
+			gaSuperBitmap[ base/64 ] |= 1LL << (base&63);
 	}
 	
 	// Set free page counts
@@ -285,7 +297,7 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 	{
 		 int	rangeID;
 		// Skip allocated
-		if( gaMainBitmap[ base >> 6 ] & (1 << (base&63))  )	continue;
+		if( gaMainBitmap[ base >> 6 ] & (1LL << (base&63))  )	continue;
 		
 		// Get range ID
 		rangeID = MM_int_GetRangeID( base << 12 );
@@ -300,57 +312,59 @@ void MM_InitPhys_Multiboot(tMBoot_Info *MBoot)
 		// updated anymore, hence will be correct)
 		giPhysRangeLast[ rangeID ] = base;
 	}
+	
+	LEAVE('-');
 }
 
 /**
  * \brief Allocate a contiguous range of physical pages with a maximum
- *        bit size of \a Bits
- * \param Num	Number of pages to allocate
- * \param Bits	Maximum size of the physical address
- * \note If \a Bits is <= 0, any sized address is used (with preference
+ *        bit size of \a MaxBits
+ * \param Pages	Number of pages to allocate
+ * \param MaxBits	Maximum size of the physical address
+ * \note If \a MaxBits is <= 0, any sized address is used (with preference
  *       to higher addresses)
  */
-tPAddr MM_AllocPhysRange(int Num, int Bits)
+tPAddr MM_AllocPhysRange(int Pages, int MaxBits)
 {
-	tPAddr	addr;
+	tPAddr	addr, ret;
 	 int	rangeID;
 	 int	nFree = 0, i;
 	
-	Log("MM_AllocPhysRange: (Num=%i,Bits=%i)", Num, Bits);
+	ENTER("iPages iBits", Pages, MaxBits);
 	
-	if( Bits <= 0 || Bits >= 64 )	// Speedup for the common case
+	if( MaxBits <= 0 || MaxBits >= 64 )	// Speedup for the common case
 		rangeID = MM_PHYS_MAX;
 	else
-		rangeID = MM_int_GetRangeID( (1 << Bits) -1 );
+		rangeID = MM_int_GetRangeID( (1LL << MaxBits) - 1 );
 	
-	Log(" MM_AllocPhysRange: rangeID = %i", rangeID);
+	LOG("rangeID = %i", rangeID);
 	
-	LOCK(&glPhysicalPages);
-	Log(" MM_AllocPhysRange: i has lock");
+	Mutex_Acquire(&glPhysicalPages);
 	
 	// Check if the range actually has any free pages
 	while(giPhysRangeFree[rangeID] == 0 && rangeID)
 		rangeID --;
 	
-	Log(" MM_AllocPhysRange: rangeID = %i", rangeID);
+	LOG("rangeID = %i", rangeID);
 	
 	// What the? Oh, man. No free pages
 	if(giPhysRangeFree[rangeID] == 0) {
-		RELEASE(&glPhysicalPages);
+		Mutex_Release(&glPhysicalPages);
 		// TODO: Page out
 		// ATM. Just Warning
 		Warning(" MM_AllocPhysRange: Out of free pages");
 		Log_Warning("Arch",
 			"Out of memory (unable to fulfil request for %i pages), zero remaining",
-			Num
+			Pages
 			);
+		LEAVE('i', 0);
 		return 0;
 	}
 	
 	// Check if there is enough in the range
-	if(giPhysRangeFree[rangeID] >= Num)
+	if(giPhysRangeFree[rangeID] >= Pages)
 	{
-		Log(" MM_AllocPhysRange: {%i,0x%x -> 0x%x}",
+		LOG("{%i,0x%x -> 0x%x}",
 			giPhysRangeFree[rangeID],
 			giPhysRangeFirst[rangeID], giPhysRangeLast[rangeID]
 			);
@@ -362,81 +376,93 @@ tPAddr MM_AllocPhysRange(int Num, int Bits)
 		{
 			//Log(" MM_AllocPhysRange: addr = 0x%x", addr);
 			// Check the super bitmap
-			if( gaSuperBitmap[addr >> (6+6)] == -1 ) {
-				Log(" MM_AllocPhysRange: nFree = %i = 0 (super) (0x%x)", nFree, addr);
+			if( gaSuperBitmap[addr >> (6+6)] + 1 == 0 ) {
+				LOG("nFree = %i = 0 (super) (0x%x)", nFree, addr);
 				nFree = 0;
-				addr += 1 << (6+6);
-				addr &= (1 << (6+6)) - 1;
+				addr += 1LL << (6+6);
+				addr &= ~0xFFF;	// (1LL << 6+6) - 1
 				continue;
 			}
 			// Check page block (64 pages)
-			if( gaSuperBitmap[addr >> (6+6)] & (1 << (addr>>6)&63)) {
-				Log(" MM_AllocPhysRange: nFree = %i = 0 (main) (0x%x)", nFree, addr);
+			if( gaMainBitmap[addr >> 6] + 1 == 0) {
+				LOG("nFree = %i = 0 (main) (0x%x)", nFree, addr);
 				nFree = 0;
-				addr += 1 << (12+6);
-				addr &= (1 << (12+6)) - 1;
+				addr += 1LL << (6);
+				addr &= ~0x3F;
 				continue;
 			}
 			// Check individual page
-			if( gaMainBitmap[addr >> 6] & (1 << (addr & 63)) ) {
-				Log(" MM_AllocPhysRange: nFree = %i = 0 (page) (0x%x)", nFree, addr);
+			if( gaMainBitmap[addr >> 6] & (1LL << (addr & 63)) ) {
+				LOG("nFree = %i = 0 (page) (0x%x)", nFree, addr);
 				nFree = 0;
 				addr ++;
 				continue;
 			}
 			nFree ++;
 			addr ++;
-			Log(" MM_AllocPhysRange: nFree(%i) == %i (0x%x)", nFree, Num, addr);
-			if(nFree == Num)
+			LOG("nFree(%i) == %i (0x%x)", nFree, Pages, addr);
+			if(nFree == Pages)
 				break;
 		}
-		Log(" MM_AllocPhysRange: nFree = %i", nFree);
+		LOG("nFree = %i", nFree);
 		// If we don't find a contiguous block, nFree will not be equal
 		// to Num, so we set it to zero and do the expensive lookup.
-		if(nFree != Num)	nFree = 0;
+		if(nFree != Pages)	nFree = 0;
 	}
 	
 	if( !nFree )
 	{
 		// Oops. ok, let's do an expensive check (scan down the list
 		// until a free range is found)
-		nFree = 1;
-		addr = giPhysRangeLast[ rangeID ];
-		// TODO
-		RELEASE(&glPhysicalPages);
+//		nFree = 1;
+//		addr = giPhysRangeLast[ rangeID ];
+		// TODO: Expensive Check
+		Mutex_Release(&glPhysicalPages);
 		// TODO: Page out
 		// ATM. Just Warning
-		Warning(" MM_AllocPhysRange: Out of memory (unable to fulfil request for %i pages)", Num);
+		Warning(" MM_AllocPhysRange: Out of memory (unable to fulfil request for %i pages)", Pages);
 		Log_Warning("Arch",
 			"Out of memory (unable to fulfil request for %i pages)",
-			Num
+			Pages	
 			);
+		LEAVE('i', 0);
 		return 0;
 	}
-	Log(" MM_AllocPhysRange: nFree = %i, addr = 0x%08x", nFree, addr);
+	LOG("nFree = %i, addr = 0x%08x", nFree, addr);
 	
 	// Mark pages as allocated
-	addr -= Num;
-	for( i = 0; i < Num; i++ )
+	addr -= Pages;
+	for( i = 0; i < Pages; i++, addr++ )
 	{
-		gaMainBitmap[addr >> 6] |= 1 << (addr & 63);
-		rangeID = MM_int_GetRangeID(addr);
+		gaMainBitmap[addr >> 6] |= 1LL << (addr & 63);
+		if( MM_GetPhysAddr( (tVAddr)&gaiPageReferences[addr] ) )
+			gaiPageReferences[addr] = 1;
+//		Log("page %P refcount = %i", MM_GetRefCount(addr<<12)); 
+		rangeID = MM_int_GetRangeID(addr << 12);
 		giPhysRangeFree[ rangeID ] --;
+		LOG("%x == %x", addr, giPhysRangeFirst[ rangeID ]);
+		if(addr == giPhysRangeFirst[ rangeID ])
+			giPhysRangeFirst[ rangeID ] += 1;
 	}
+	addr -= Pages;
+	ret = addr;	// Save the return address
 	
 	// Update super bitmap
-	Num += addr & (64-1);
+	Pages += addr & (64-1);
 	addr &= ~(64-1);
-	Num = (Num + (64-1)) & ~(64-1);
-	for( i = 0; i < Num/64; i++ )
+	Pages = (Pages + (64-1)) & ~(64-1);
+	for( i = 0; i < Pages/64; i++ )
 	{
-		if( gaMainBitmap[ addr >> 6 ] == -1 )
-			gaSuperBitmap[addr>>12] |= 1 << ((addr >> 6) & 64);
+		if( gaMainBitmap[ addr >> 6 ] + 1 == 0 )
+			gaSuperBitmap[addr>>12] |= 1LL << ((addr >> 6) & 63);
 	}
 	
-	RELEASE(&glPhysicalPages);
-	Log("MM_AllocPhysRange: RETURN %x", addr << 12);
-	return addr << 12;
+	Mutex_Release(&glPhysicalPages);
+	#if TRACE_REF
+	Log("MM_AllocPhysRange: ret = %P (Ref %i)", ret << 12, MM_GetRefCount(ret<<12));
+	#endif
+	LEAVE('x', ret << 12);
+	return ret << 12;
 }
 
 /**
@@ -452,7 +478,7 @@ tPAddr MM_AllocPhys(void)
 		if( gaiStaticAllocPages[i] ) {
 			tPAddr	ret = gaiStaticAllocPages[i];
 			gaiStaticAllocPages[i] = 0;
-			Log("MM_AllocPhys: Return %x, static alloc %i", ret, i);
+			Log("MM_AllocPhys: Return %P, static alloc %i", ret, i);
 			return ret;
 		}
 	}
@@ -467,21 +493,43 @@ void MM_RefPhys(tPAddr PAddr)
 {
 	Uint64	page = PAddr >> 12;
 	
-	if( PAddr >> 12 > giMaxPhysPage )	return ;
+	if( page > giMaxPhysPage )	return ;
 	
-	if( gaMainBitmap[ page >> 6 ] & (1 << (page&63)) )
+	if( PAGE_ALLOC_TEST(page) )
 	{
-		// Reference again
-		gaMultiBitmap[ page >> 6 ] |= 1 << (page&63);
-		gaiPageReferences[ page ] ++;
+		tVAddr	ref_base = ((tVAddr)&gaiPageReferences[ page ]) & ~0xFFF;
+		// Allocate reference page
+		if( !MM_GetPhysAddr(ref_base) )
+		{
+			const int	pages_per_refpage = PAGE_SIZE/sizeof(gaiPageReferences[0]);
+			 int	i;
+			 int	page_base = page / pages_per_refpage * pages_per_refpage;
+			if( !MM_Allocate( ref_base ) ) {
+				Log_Error("Arch", "Out of memory when allocating reference count page");
+				return ;
+			}
+			// Fill block
+			Log("Allocated references for %P-%P", page_base << 12, (page_base+pages_per_refpage)<<12);
+			for( i = 0; i < pages_per_refpage; i ++ ) {
+				 int	pg = page_base + i;
+				gaiPageReferences[pg] = !!PAGE_ALLOC_TEST(pg);
+			}
+		}
+		gaiPageReferences[page] ++;
 	}
 	else
 	{
 		// Allocate
-		gaMainBitmap[page >> 6] |= 1 << (page&63);
-		if( gaMainBitmap[page >> 6 ] == -1 )
-			gaSuperBitmap[page>> 12] |= 1 << ((page >> 6) & 63);
+		PAGE_ALLOC_SET(page);
+		if( gaMainBitmap[page >> 6] + 1 == 0 )
+			gaSuperBitmap[page>> 12] |= 1LL << ((page >> 6) & 63);
+		if( MM_GetPhysAddr( (tVAddr)&gaiPageReferences[page] ) )
+			gaiPageReferences[page] = 1;
 	}
+
+	#if TRACE_REF
+	Log("MM_RefPhys: %P referenced (%i)", page << 12, MM_GetRefCount(page << 12));
+	#endif
 }
 
 /**
@@ -493,27 +541,52 @@ void MM_DerefPhys(tPAddr PAddr)
 	
 	if( PAddr >> 12 > giMaxPhysPage )	return ;
 	
-	if( gaMultiBitmap[ page >> 6 ] & (1 << (page&63)) ) {
+	if( MM_GetPhysAddr( (tVAddr) &gaiPageReferences[page] ) )
+	{
 		gaiPageReferences[ page ] --;
-		if( gaiPageReferences[ page ] == 1 )
-			gaMultiBitmap[ page >> 6 ] &= ~(1 << (page&63));
 		if( gaiPageReferences[ page ] == 0 )
-			gaMainBitmap[ page >> 6 ] &= ~(1 << (page&63));
+			PAGE_ALLOC_CLEAR(page);
 	}
 	else
-		gaMainBitmap[ page >> 6 ] &= ~(1 << (page&63));
+		PAGE_ALLOC_CLEAR(page);
 	
-	// TODO: Update free counts
-	if( !(gaMainBitmap[ page >> 6 ] & (1 << (page&63))) )
+	// Update the free counts if the page was freed
+	if( !PAGE_ALLOC_TEST(page) )
 	{
 		 int	rangeID;
 		rangeID = MM_int_GetRangeID( PAddr );
 		giPhysRangeFree[ rangeID ] ++;
+		if( giPhysRangeFirst[rangeID] > page )
+			giPhysRangeFirst[rangeID] = page;
+		if( giPhysRangeLast[rangeID] < page )
+			giPhysRangeLast[rangeID] = page;
 	}
 	
-	if(gaMainBitmap[ page >> 6 ] == 0) {
-		gaSuperBitmap[page >> 12] &= ~(1 << ((page >> 6) & 63));
+	// If the bitmap entry is not -1, unset the bit in the super bitmap
+	if(gaMainBitmap[ page >> 6 ] + 1 != 0 ) {
+		gaSuperBitmap[page >> 12] &= ~(1LL << ((page >> 6) & 63));
 	}
+	
+	#if TRACE_REF
+	Log("Page %P dereferenced (%i)", page << 12, MM_GetRefCount(page << 12));
+	#endif
+}
+
+int MM_GetRefCount( tPAddr PAddr )
+{
+	PAddr >>= 12;
+	
+	if( PAddr > giMaxPhysPage )	return 0;
+
+	if( MM_GetPhysAddr( (tVAddr)&gaiPageReferences[PAddr] ) ) {
+		return gaiPageReferences[PAddr];
+	}
+
+	if( PAGE_ALLOC_TEST(PAddr) )
+	{
+		return 1;
+	}
+	return 0;
 }
 
 /**
@@ -534,3 +607,35 @@ int MM_int_GetRangeID( tPAddr Addr )
 	else
 		return MM_PHYS_16BIT;
 }
+
+int MM_SetPageNode(tPAddr PAddr, void *Node)
+{
+	tPAddr	page = PAddr >> 12;
+	tVAddr	node_page = ((tVAddr)&gapPageNodes[page]) & ~(PAGE_SIZE-1);
+
+//	if( !MM_GetRefCount(PAddr) )	return 1;
+	
+	if( !MM_GetPhysAddr(node_page) ) {
+		if( !MM_Allocate(node_page) )
+			return -1;
+		memset( (void*)node_page, 0, PAGE_SIZE );
+	}
+
+	gapPageNodes[page] = Node;
+	return 0;
+}
+
+int MM_GetPageNode(tPAddr PAddr, void **Node)
+{
+//	if( !MM_GetRefCount(PAddr) )	return 1;
+	PAddr >>= 12;
+	
+	if( !MM_GetPhysAddr( (tVAddr)&gapPageNodes[PAddr] ) ) {
+		*Node = NULL;
+		return 0;
+	}
+
+	*Node = gapPageNodes[PAddr];
+	return 0;
+}
+