internal static bool TryReservePages(Thread currentThread,
UIntPtr startPage,
UIntPtr pageCount,
PageType newType,
ref bool fCleanPages)
{
Trace.Log(Trace.Area.Page,
"TryReservePages start={0:x} count={1:x}",
__arglist(startPage, pageCount));
VTable.Deny(PageTable.IsUnusedPageType(newType));
VTable.Assert(pageCount > UIntPtr.Zero);
VTable.Deny(startPage != UIntPtr.Zero &&
PageTable.IsUnusedPage(startPage - 1) &&
PageTable.IsMyPage(startPage - 1));
UIntPtr endPage = startPage + pageCount;
UIntPtr index = startPage;
while (index < endPage &&
PageTable.IsUnusedPage(index) &&
PageTable.IsMyPage(index))
{
index++;
}
if (PageTable.IsUnallocatedPage(PageTable.Type(index)))
{
// We should try to extend the region of allocated pages
UIntPtr pagesNeeded = pageCount - (index - startPage);
UIntPtr bytesNeeded = PageTable.RegionSize(pagesNeeded);
UIntPtr allocSize = Util.Pad(bytesNeeded, heap_commit_size);
UIntPtr startAddr = PageTable.PageAddr(index);
bool gotMemory = false;
bool iflag = EnterMutex(currentThread);
try {
gotMemory =
MemoryManager.AllocateMemory(startAddr, allocSize);
if (gotMemory)
{
UIntPtr allocPages = PageTable.PageCount(allocSize);
MarkUnusedPages(/* avoid recursive locking */ null,
index, allocPages, true);
}
} finally {
LeaveMutex(currentThread, iflag);
}
if (gotMemory)
{
bool success =
TryReserveUnusedPages(currentThread, startPage,
pageCount, newType,
ref fCleanPages);
Trace.Log(Trace.Area.Page,
"TryReservePages success={0}",
__arglist(success));
return(success);
}
}
return(false);
}
private static void EnsureMutatorControlNoGC(ref int statusWord,
int currentThreadIndex)
{
if (!fInMutatorState(statusWord))
{
TakeMutatorControlNoGC(ref statusWord, currentThreadIndex);
}
VTable.Deny(fInDormantState(statusWord));
VTable.Deny(fUnderGCControl(statusWord));
}
private static bool SwitchToMutatorState(ref int statusWord)
{
VTable.Deny(fInMutatorState(statusWord),
"Thread is already under mutator control");
VTable.Assert(fInDormantState(statusWord));
int oldValue = statusWord & ~(GCRequest | GCControl);
int newValue = (oldValue | MutatorState) & ~DormantState;
return(CompareAndSwap(ref statusWord, newValue, oldValue));
}
private static void TakeMutatorControlNoGC(ref int statusWord,
int currentThreadIndex)
{
if (!SwitchToMutatorState(ref statusWord))
{
TakeMutatorControlSlowNoGC(ref statusWord, currentThreadIndex);
}
VTable.Assert(fInMutatorState(statusWord));
VTable.Deny(fInDormantState(statusWord));
VTable.Deny(fUnderGCControl(statusWord));
}
private static void TakeDormantControlNoGC(ref int statusWord)
{
VTable.Assert(fInMutatorState(statusWord));
VTable.Deny(fInDormantState(statusWord));
int oldValue, newValue;
do
{
oldValue = statusWord;
newValue = (oldValue | DormantState) & ~MutatorState;
} while (!CompareAndSwap(ref statusWord, newValue, oldValue));
}
internal void ClearCalleeReg()
{
VTable.Deny(this.pending);
UIntPtr *scan = this.head;
while (scan != null)
{
UIntPtr temp = *scan;
* scan = value;
scan = (UIntPtr *)temp;
}
this.head = null;
}
private static void LinkUnusedPages(UIntPtr startPage,
UIntPtr pageCount,
bool asVictim)
{
if (PageManager.SlowDebug)
{
for (UIntPtr i = startPage; i < startPage + pageCount; i++)
{
VTable.Assert(PageTable.IsUnusedPage(i) &&
PageTable.IsMyPage(i),
"Incorrect page to link into unused region");
}
}
Trace.Log(Trace.Area.Page,
"LinkUnusedPages start={0:x} count={1:x}",
__arglist(startPage, pageCount));
VTable.Deny(startPage > UIntPtr.Zero &&
PageTable.IsUnusedPage(startPage - 1) &&
PageTable.IsMyPage(startPage - 1));
VTable.Deny(startPage + pageCount > PageTable.pageTableCount);
VTable.Deny(startPage + pageCount < PageTable.pageTableCount &&
PageTable.IsUnusedPage(startPage + pageCount) &&
PageTable.IsMyPage(startPage + pageCount));
UnusedBlockHeader *header = (UnusedBlockHeader *)
PageTable.PageAddr(startPage);
UnusedBlockHeader.Initialize(header, pageCount);
int slot = SlotFromCount(pageCount);
// Unused blocks are linked into the free list either as the result of a collection
// or as a result of carving a big block into a smaller allocation and a remainder.
// When such a remainder is linked back into the free list, it is identified as a
// victim. We favor subsequent allocations from these victims, in an attempt to
// reduce fragmentation. This is achieved by keeping victims at the head of the
// free list.
//
// TODO: the long term solution is to perform best fit on the free list.
if (asVictim || unusedMemoryBlocks[slot].next == null)
{
fixed(UnusedBlockHeader *listHeader = &unusedMemoryBlocks[slot])
{
UnusedBlockHeader.InsertNext(listHeader, header);
}
}
else
{
UnusedBlockHeader *listHeader = unusedMemoryBlocks[slot].next;
UnusedBlockHeader.InsertNext(listHeader, header);
}
}
private static UIntPtr UnlinkUnusedPages(UIntPtr startPage)
{
VTable.Assert(PageTable.IsUnusedPage(startPage) &&
PageTable.IsMyPage(startPage));
VTable.Deny(startPage > UIntPtr.Zero &&
PageTable.IsUnusedPage(startPage - 1) &&
PageTable.IsMyPage(startPage - 1));
UnusedBlockHeader *header = (UnusedBlockHeader *)
PageTable.PageAddr(startPage);
UIntPtr pageCount = UnusedBlockHeader.Remove(header);
Trace.Log(Trace.Area.Page,
"UnlinkUnusedPages start={0:x} count={1:x}",
__arglist(startPage, pageCount));
return(pageCount);
}
private static void TakeDormantControl(ref int statusWord,
int threadIndex)
{
VTable.Assert(fInMutatorState(statusWord));
VTable.Deny(fInDormantState(statusWord));
int oldValue, newValue;
do
{
oldValue = statusWord;
newValue = (oldValue | DormantState) & ~MutatorState;
} while (!CompareAndSwap(ref statusWord, newValue, oldValue));
if (fHasGCRequest(newValue))
{
GC.ThreadDormantGCNotification(threadIndex);
}
}
private static UIntPtr FindUnusedPages(Thread currentThread,
UIntPtr pageCount,
PageType newType)
{
VTable.Deny(PageTable.IsUnusedPageType(newType));
int slot = SlotFromCount(pageCount);
Trace.Log(Trace.Area.Page,
"FindUnusedPages count={0:x} slot={1}",
__arglist(pageCount, slot));
bool iflag = EnterMutex(currentThread);
try {
while (slot < 32)
{
UnusedBlockHeader *header = unusedMemoryBlocks[slot].next;
while (header != null)
{
if (header->count >= pageCount)
{
UIntPtr startPage =
PageTable.Page((UIntPtr)header);
UIntPtr regionSize = UnlinkUnusedPages(startPage);
SetPageTypeClean(startPage, pageCount, newType);
if (regionSize > pageCount)
{
UIntPtr restCount = regionSize - pageCount;
UIntPtr endPage = startPage + pageCount;
LinkUnusedPages(endPage, restCount, true);
}
Trace.Log(Trace.Area.Page,
"FindUnusedPages success {0:x}",
__arglist(startPage));
return(startPage);
}
header = header->next;
}
slot++;
}
return(UIntPtr.Zero);
} finally {
LeaveMutex(currentThread, iflag);
}
}
public void VerifyHeap()
{
// Temporarily set the thread allocation point to the unused
// space token, if necessary.
Thread currentThread = Thread.CurrentThread;
VerifyAllThreadsGCControlled(currentThread);
// Do the real work
VerifyPages(this.objectVisitor);
StaticData.ScanStaticData(this.referenceVisitor);
VTable.Deny(PageTable.IsUnusedPage(PageTable.Page(Magic.addressOf(Thread.threadTable))));
for (int i = 0; i < Thread.threadTable.Length; i++)
{
Thread t = Thread.threadTable[i];
if (t != null)
{
VTable.Deny(PageTable.IsUnusedPage(PageTable.Page(Magic.addressOf(t))));
this.stackVerifier.Verify(this.threadReferenceVisitor,
t);
}
}
}
internal void ScanLiveReg(uint kind,
NonNullReferenceVisitor visitor)
{
switch (kind)
{
case 0: {
// Value is not a traceable heap pointer
break;
}
case 1: {
// Value is a pointer variable
VTable.Deny(this.head == null);
if (value != UIntPtr.Zero)
{
fixed(UIntPtr *valueField = &this.value)
{
visitor.Visit(valueField);
}
}
ClearCalleeReg();
break;
}
case 2: {
// Value is unchanged since function entry
VTable.Deny(this.pending);
this.pending = true;
break;
}
case 3:
default: {
VTable.NotReached("ScanLiveReg 3 or default");
break;
}
}
}
internal static unsafe bool AllocateMemory(UIntPtr startAddr,
UIntPtr size)
{
VTable.Deny(inAllocator);
inAllocator = true;
VTable.Assert(PageTable.PageAligned(startAddr));
VTable.Assert(PageTable.PageAligned(size));
#if SINGULARITY_KERNEL
UIntPtr addr = Sing_MemoryManager.KernelExtend(
startAddr, Sing_MemoryManager.PagesFromBytes(size),
Process.kernelProcess, PageType.Unknown);
#elif SINGULARITY_PROCESS
UIntPtr addr = PageTableService.AllocateExtend(startAddr, size);
#endif
inAllocator = false;
if (addr != UIntPtr.Zero)
{
Util.MemClear(addr, size);
return(true);
}
return(false);
}
internal static void EnsureAllocationAllowed()
{
// Verify that we're not in an interrupt or non-preemptible region where allocations are prohibited
Microsoft.Singularity.Processor currentProcessor = Microsoft.Singularity.Processor.CurrentProcessor;
if (currentProcessor != null) // The Processor object itself may still need to be allocated
{
if (currentProcessor.InInterruptContext)
{
Tracing.Log(Tracing.Fatal, "Attempt to allocate memory from interrupt context!");
VTable.DebugPrint("Attempt to allocate memory from interrupt context!\n");
VTable.DebugBreak();
}
#if false // Currently too many allocations with preemption disabled to debug right now
if (currentProcessor.PreemptionDisabled)
{
VTable.DebugPrint("Attempt to allocate memory with preemption disabled!\n");
VTable.DebugBreak();
}
#endif
}
VTable.Deny(Thread.CurrentThread != null &&
Transitions.fInitializedRuntime &&
Transitions.UnderGCControl(Thread.GetCurrentThreadIndex()));
}
internal static UIntPtr EnsurePages(Thread currentThread,
UIntPtr pageCount,
PageType newType,
ref bool fCleanPages)
{
if (currentThread != null)
{
GC.CheckForNeededGCWork(currentThread);
}
VTable.Deny(PageTable.IsUnusedPageType(newType));
// Try to find already allocated but unused pages
UIntPtr foundPages =
FindUnusedPages(currentThread, pageCount, newType);
if (foundPages != UIntPtr.Zero)
{
if (fCleanPages)
{
CleanFoundPages(foundPages);
}
else
{
fCleanPages = FoundOnlyCleanPages(foundPages);
}
return(foundPages);
}
// We need to allocate new pages
bool iflag = EnterMutex(currentThread);
try {
UIntPtr bytesNeeded = PageTable.RegionSize(pageCount);
UIntPtr allocSize = Util.Pad(bytesNeeded, heap_commit_size);
UIntPtr startAddr = MemoryManager.AllocateMemory(allocSize);
if (startAddr == UIntPtr.Zero)
{
if (heap_commit_size > os_commit_size)
{
allocSize = Util.Pad(bytesNeeded, os_commit_size);
startAddr = MemoryManager.AllocateMemory(allocSize);
}
}
if (startAddr == UIntPtr.Zero)
{
// BUGBUG: if in CMS, should wait on one complete GC cycle and
// the retry. for STW, we may get here even if the collector
// hasn't triggered just prior.
PageTable.Dump("Out of memory");
throw outOfMemoryException;
}
UIntPtr startPage = PageTable.Page(startAddr);
PageTable.SetType(startPage, pageCount, newType);
PageTable.SetProcess(startPage, pageCount);
UIntPtr extraPages =
PageTable.PageCount(allocSize) - pageCount;
if (extraPages > 0)
{
// Mark the new memory pages as allocated-but-unused
MarkUnusedPages(/* avoid recursive locking */ null,
startPage + pageCount, extraPages,
true);
}
return(startPage);
} finally {
LeaveMutex(currentThread, iflag);
}
}
internal void Write(UIntPtr value)
{
VTable.Deny(this.IsEmpty);
*this.cursor++ = value;
}
internal static bool TryReserveUnusedPages(Thread currentThread,
UIntPtr startPage,
UIntPtr pageCount,
PageType newType,
ref bool fCleanPages)
{
Trace.Log(Trace.Area.Page,
"TryReserveUnusedPages start={0:x} count={1:x}",
__arglist(startPage, pageCount));
VTable.Deny(PageTable.IsUnusedPageType(newType));
VTable.Assert(pageCount > UIntPtr.Zero);
VTable.Deny(startPage != UIntPtr.Zero &&
PageTable.IsUnusedPage(startPage - 1) &&
PageTable.IsMyPage(startPage - 1));
UIntPtr endPage = startPage + pageCount;
if (endPage > PageTable.pageTableCount)
{
return(false);
}
if (currentThread != null)
{
GC.CheckForNeededGCWork(currentThread);
}
bool iflag = EnterMutex(currentThread);
try {
// GC can occur and page can be collected.
if (startPage != UIntPtr.Zero &&
PageTable.IsUnusedPage(startPage - 1))
{
return(false);
}
if (!PageTable.IsUnusedPage(startPage) ||
!PageTable.IsMyPage(startPage))
{
return(false);
}
UnusedBlockHeader *header = (UnusedBlockHeader *)
PageTable.PageAddr(startPage);
if (header->count < pageCount)
{
return(false);
}
UIntPtr regionPages = UnlinkUnusedPages(startPage);
Trace.Log(Trace.Area.Page,
"TryReserveUnusedPages found={0:x}",
__arglist(regionPages));
SetPageTypeClean(startPage, pageCount, newType);
if (regionPages > pageCount)
{
UIntPtr suffixPages = regionPages - pageCount;
LinkUnusedPages(endPage, suffixPages, true);
}
} finally {
LeaveMutex(currentThread, iflag);
}
// Now that we are outside the Mutex, we should perform the
// real cleaning of the gotten pages
if (fCleanPages)
{
CleanFoundPages(startPage);
}
else
{
fCleanPages = FoundOnlyCleanPages(startPage);
}
return(true);
}
internal UIntPtr Read()
{
VTable.Deny(this.IsEmpty);
return(*this.cursor++);
}
