private UIntPtr AllocateObjectMemorySlow(UIntPtr numBytes,
uint alignment,
Thread currentThread)
{
//Trace.Log(Trace.Area.Allocate,
// "AllocateObjectMemorySlow numBytes={0}, alignment={1}, currentThread={2}", __arglist(numBytes, alignment, currentThread));
GC.CheckForNeededGCWork(currentThread);
VTable.Assert(CurrentPhase != StopTheWorldPhase.SingleThreaded ||
currentThread.threadIndex == collectorThreadIndex);
if (GenerationalCollector.IsLargeObjectSize(numBytes))
{
return(AllocateBig(numBytes, alignment, currentThread));
}
return(BumpAllocator.Allocate(currentThread, numBytes, alignment));
}
// Interface with the compiler!
internal static unsafe UIntPtr AllocateBig(UIntPtr numBytes,
uint alignment,
Thread currentThread)
{
// Pretenure Trigger
pretenuredSinceLastFullGC += numBytes;
if (pretenuredSinceLastFullGC > PretenureHardGCTrigger)
{
GC.InvokeMajorCollection(currentThread);
}
// Potentially Join a collection
GC.CheckForNeededGCWork(currentThread);
int maxAlignmentOverhead = unchecked ((int)alignment) - UIntPtr.Size;
UIntPtr pageCount =
PageTable.PageCount(numBytes + maxAlignmentOverhead);
bool fCleanPages = true;
UIntPtr page = PageManager.EnsurePages(currentThread, pageCount,
largeObjectGeneration,
ref fCleanPages);
int unusedBytes =
unchecked ((int)(PageTable.RegionSize(pageCount) - numBytes));
int unusedCacheLines =
unchecked ((int)(unusedBytes - maxAlignmentOverhead)) >> 5;
int pageOffset = 0;
if (unusedCacheLines != 0)
{
pageOffset = (bigOffset % unusedCacheLines) << 5;
bigOffset++;
}
UIntPtr pageStart = PageTable.PageAddr(page);
for (int i = 0; i < pageOffset; i += UIntPtr.Size)
{
Allocator.WriteAlignment(pageStart + i);
}
UIntPtr unalignedStartAddr = pageStart + pageOffset;
UIntPtr startAddr =
Allocator.AlignedAllocationPtr(unalignedStartAddr,
pageStart + unusedBytes,
alignment);
pageOffset +=
unchecked ((int)(uint)(startAddr - unalignedStartAddr));
if (pageOffset < unusedBytes)
{
BumpAllocator.WriteUnusedMarker(pageStart + pageOffset + numBytes);
}
UIntPtr resultAddr = startAddr + PreHeader.Size;
InteriorPtrTable.SetFirst(resultAddr);
VTable.Assert(PageTable.Page(resultAddr) <
PageTable.Page(startAddr + numBytes - 1),
"Big object should cross pages");
if (GC.remsetType == RemSetType.Cards)
{
#if DONT_RECORD_OBJALLOC_IN_OFFSETTABLE
#else
OffsetTable.SetLast(resultAddr);
#endif
}
return(resultAddr);
}
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 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);
}
}