internal static void Initialize()
{
// The card table covers all the heap. Below is not accurate heap
// size. It includes all the memory space, starting from address 0.
// TODO: find more accurate heap size and start
UIntPtr heapSize = PageTable.pageTableCount * PageTable.PageSize;
VTable.Assert((heapSize >> CardBits) << CardBits == heapSize,
"Assumption: pageSize is expected to be multiple of CardSize");
UIntPtr heapStart = (UIntPtr)0;
totalCards = heapSize >> CardBits;
firstCardNo = heapStart >> CardBits;
UIntPtr tablePtr = PageManager.AllocateNonheapMemory(null, totalCards);
VTable.Assert(tablePtr != UIntPtr.Zero);
cardTablePtr = (byte *)tablePtr;
cardTableBase = (byte *)(tablePtr - firstCardNo);
CardTable.instance = (CardTable)
BootstrapMemory.Allocate(typeof(CardTable));
OffsetTable.Initialize(totalCards);
for (UIntPtr c = firstCardNo; c < firstCardNo + totalCards; c++)
{
VTable.Assert(!CardIsDirty(c), "Card table initialization error");
}
}
internal override UIntPtr Visit(Object obj)
{
#if DEBUG_OFFSETTABLE
VTable.DebugPrint("visit obj {0:x8}\n", __arglist(Magic.addressOf(obj)));
if (lastObjPtr != UIntPtr.Zero)
{
UIntPtr lastCard = CardTable.CardNo(lastObjPtr);
if (lastCard != CardTable.CardNo(Magic.addressOf(obj)))
{
if (!OffsetTable.NoObjectPtrToTheCard(lastCard))
{
UIntPtr realOffst = lastObjPtr - CardTable.CardAddr(lastCard);
UIntPtr currOffst = OffsetTable.GetOffset(lastCard);
if (realOffst != currOffst)
{
VTable.DebugPrint("Verifier: wrong offset. Card {0:x8} Offset {1:x8} Should be {2:x8}\n",
__arglist(lastCard, currOffst, realOffst));
VTable.Assert(false);
}
}
}
}
#endif
return(this.referenceVisitor.VisitReferenceFields(obj));
}
private UIntPtr FreshAlloc(UIntPtr bytes, uint alignment,
Thread currentThread)
{
#if SINGULARITY_KERNEL
Kernel.Waypoint(702);
#endif
this.Truncate();
UIntPtr paddedBytes =
PageTable.PagePad(bytes + alignment - UIntPtr.Size);
BaseCollector.IncrementNewBytesSinceGC(paddedBytes);
UIntPtr pages = PageTable.PageCount(paddedBytes);
bool fCleanPages = CLEAR_POOL_PAGES();
// We may eventually want to ask for specific pages
// between asking if any pages are reusable and asking the
// OS for any possible page.
UIntPtr startPage =
PageManager.EnsurePages(currentThread, pages, this.pageType,
ref fCleanPages);
UIntPtr startAddr = PageTable.PageAddr(startPage);
UIntPtr limitAddr = PageTable.PageAddr(startPage + pages);
startAddr = Allocator.AlignedAllocationPtr(startAddr, limitAddr,
alignment);
this.allocNew = startAddr;
this.allocPtr = startAddr + bytes;
if (fCleanPages)
{
this.zeroedLimit = limitAddr;
}
else
{
Util.MemClear(startAddr, bytes);
this.zeroedLimit = this.allocPtr;
}
this.reserveLimit = limitAddr;
UIntPtr resultAddr = startAddr + PreHeader.Size;
InteriorPtrTable.SetFirst(resultAddr);
#if !SINGULARITY || SEMISPACE_COLLECTOR || ADAPTIVE_COPYING_COLLECTOR || SLIDING_COLLECTOR
if (GC.remsetType == RemSetType.Cards)
{
UIntPtr nextPageAddr = startAddr + PageTable.PageSize;
VTable.Assert(resultAddr < nextPageAddr);
if (this.allocPtr > nextPageAddr)
{
#if DONT_RECORD_OBJALLOC_IN_OFFSETTABLE
#else
OffsetTable.SetLast(resultAddr);
#endif
}
}
#endif
#if SINGULARITY_KERNEL
Kernel.Waypoint(703);
#endif
return(resultAddr);
}
private unsafe void SkipDestinationAreas(ref UIntPtr destPage,
UIntPtr destCursor,
ref UIntPtr destLimit,
UIntPtr sourceCursor)
{
UIntPtr cursorPage = PageTable.Page(destCursor);
UIntPtr sourcePage = PageTable.Page(sourceCursor);
if (cursorPage != sourcePage)
{
UIntPtr destPageLimit = PageTable.PagePad(destCursor);
if (destPageLimit != destCursor)
{
cursorPage++;
}
VTable.Assert(PageTable.PageAligned(destLimit));
UIntPtr limitPage = PageTable.Page(destLimit);
while (destPage < sourcePage)
{
if (cursorPage < limitPage)
{
this.RegisterSkippedPages(cursorPage, limitPage);
}
do
{
destPage++;
} while (!IsMyZombiePage(destPage));
cursorPage = destPage;
do
{
destPage++;
} while (IsMyZombiePage(destPage));
limitPage = destPage;
}
destLimit = PageTable.PageAddr(limitPage);
VTable.Assert(destPage > sourcePage);
VTable.Assert(cursorPage <= sourcePage);
if (cursorPage < sourcePage)
{
this.RegisterSkippedPages(cursorPage, sourcePage);
cursorPage = sourcePage;
}
InteriorPtrTable.ClearFirst(cursorPage, destPage);
InteriorPtrTable.SetFirst(sourceCursor + PreHeader.Size);
if (GC.remsetType == RemSetType.Cards)
{
OffsetTable.ClearLast(PageTable.PageAddr(cursorPage),
PageTable.PageAddr(destPage) - 1);
}
}
}
private void CompactPhaseCleanup(Thread currentThread,
PageType generation,
UIntPtr newLimitPtr)
{
VTable.Assert(IsValidGeneration((int)generation));
registerThreadReferenceVisitor.Cleanup();
// Free up skipped pages
while (!this.skippedPageQueue.IsEmpty)
{
UIntPtr start = this.skippedPageQueue.Read();
UIntPtr finish = this.skippedPageQueue.Read();
InteriorPtrTable.ClearFirst(start, finish);
PageManager.FreePageRange(start, finish);
if (GC.remsetType == RemSetType.Cards)
{
OffsetTable.ClearLast(PageTable.PageAddr(start),
PageTable.PageAddr(finish) - 1);
}
}
this.skippedPageQueue.Cleanup(true);
// Release the queue standby pages
UnmanagedPageList.ReleaseStandbyPages();
// Update the ownership information for the copied data
PageType destGeneration =
(generation == MAX_GENERATION) ?
MAX_GENERATION :
(PageType)(generation + 1);
UIntPtr limitPage =
PageTable.Page(PageTable.PagePad(newLimitPtr));
for (UIntPtr i = UIntPtr.Zero; i < limitPage; i++)
{
if (IsMyZombiePage(i))
{
PageTable.SetType(i, (PageType)destGeneration);
}
}
}
private static void VisitObjectsInCards(NonNullReferenceVisitor ptrVisitor,
UIntPtr first, UIntPtr last)
{
UIntPtr objectPtr = OffsetTable.FirstObjPtrWithFieldInCard(first);
VTable.Assert(objectPtr != UIntPtr.Zero, "No first obj ptr");
// TODO: in semispace.Visit, update cards in visiting promoted objects.
// So far, since we have only two generations, and after scanning, all nursery
// objects are promoted to mature generation, thus there is no inter-generational
// pointers anymore, and we do not need to update cards during visit. But we
// need to do that once we have more than two generations.
UIntPtr limit = NextCardAddr(last);
while (objectPtr != UIntPtr.Zero && objectPtr < limit)
{
#if DEBUG_CARDS
VTable.DebugPrint(" visiting obj ptr {0:x8}\n", __arglist(objectPtr));
#endif
Object obj = Magic.fromAddress(objectPtr);
UIntPtr objSize = ptrVisitor.VisitReferenceFields(obj);
UIntPtr nextObjectPtr = OffsetTable.PtrToNextObject(objectPtr, objSize, limit);
VTable.Assert(CardNo(objectPtr) <= CardNo(nextObjectPtr),
"Next object should be below the current one");
if (CardNo(objectPtr) < CardNo(nextObjectPtr))
{
UIntPtr c = CardNo(objectPtr);
UIntPtr offset = objectPtr - CardAddr(c);
if (offset > OffsetTable.GetOffset(c))
{
OffsetTable.SetOffset(c, offset);
}
}
objectPtr = nextObjectPtr;
}
}
internal static UIntPtr FirstObjPtrWithFieldInCard(UIntPtr c)
{
VTable.Assert(CardTable.IsValidCardNo(c), "Not valid card no");
VTable.Assert(CardTable.IsMyLiveGcCard(c), "Not my live GC card");
UIntPtr cardAddr = CardTable.CardAddr(c);
UIntPtr nextCardAddr = CardTable.NextCardAddr(c);
// Scan backward. May go to zombie areas
UIntPtr cardBefore = c - 1;
while (cardBefore >= CardTable.FirstCardNo &&
OffsetTable.NoObjectPtrToTheCard(cardBefore) &&
CardTable.IsMyGcCard(cardBefore))
{
cardBefore--;
}
UIntPtr ptr;
if (cardBefore < CardTable.FirstCardNo ||
!CardTable.IsMyGcCard(cardBefore))
{
// this case happens when c is the first live card that has an object.
VTable.Assert(CardTable.IsMyGcCard(cardBefore + 1),
"The next card must be a GC card");
VTable.Assert(CardTable.CardAddr(cardBefore + 1) ==
CardTable.PageAddrOfCard(cardBefore + 1),
"The next card must be at the boundary of a page");
UIntPtr pageAddr = CardTable.PageAddrOfCard(cardBefore + 1);
ptr = PtrToNextObject(pageAddr, (UIntPtr)PreHeader.Size, nextCardAddr);
}
else
{
VTable.Assert(!OffsetTable.NoObjectPtrToTheCard(cardBefore),
"A card with an object must have been found");
ptr = CardTable.CardAddr(cardBefore) +
OffsetTable.GetOffset(cardBefore);
}
VTable.Assert(ptr < nextCardAddr, "No objptr in this card");
// Scan forward. Update offset table in the course.
UIntPtr currentPtr = ptr;
while (currentPtr < cardAddr)
{
UIntPtr size = OffsetTable.ObjectSize(currentPtr);
if (currentPtr + size - PreHeader.Size > cardAddr)
{
VTable.Assert(CardTable.CardGeneration(CardTable.CardNo(currentPtr)) ==
CardTable.CardGeneration(c),
"The whole object must be in the same generation");
break;
}
else
{
ptr = currentPtr;
currentPtr = PtrToNextObject(currentPtr, size, nextCardAddr);
VTable.Assert(CardTable.CardNo(ptr) <= CardTable.CardNo(currentPtr),
"Previous ptr should be before current ptr");
if (CardTable.CardNo(ptr) < CardTable.CardNo(currentPtr))
{
UIntPtr ptrC = CardTable.CardNo(ptr);
UIntPtr offsetC = ptr - CardTable.CardAddr(ptrC);
if (offsetC > GetOffset(ptrC))
{
SetOffset(ptrC, offsetC);
}
}
}
}
VTable.Assert(currentPtr != UIntPtr.Zero, "current ptr is zero");
VTable.Assert(currentPtr < nextCardAddr, "No objptr found in this card");
#if DEBUG_OFFSETTABLE
UIntPtr temp = OffsetTable.FirstPtrFromInteriorTable(c);
if (temp != currentPtr)
{
VTable.DebugPrint("Found ptr ({0:x8}) inconsistent with first ptr from interior table({1:x8})\n",
__arglist(currentPtr, temp));
VTable.Assert(false);
}
#endif
return(currentPtr);
}
// 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 void ReclaimZombiePages(UIntPtr heapPageCount,
int generation)
{
// to indicate if we want to release pages back to the OS
bool releasePages = true;
UIntPtr reservePages = UIntPtr.Zero;
if (generation == (int)nurseryGeneration)
{
// don't bother when we do nursery collection since
// nursery size is small.
releasePages = false;
}
else
{
reservePages = heapPageCount;
UIntPtr alreadyReservedPages = PageManager.TotalUnusedPages();
if (reservePages > alreadyReservedPages)
{
reservePages = reservePages - alreadyReservedPages;
}
else
{
reservePages = UIntPtr.Zero;
}
}
// MarkZombiePages updates the range for this generation, so we do
// not need to take the union ranges of all target generations
UIntPtr minZombiePage = MinGenPage[generation];
UIntPtr maxZombiePage = MaxGenPage[generation];
for (UIntPtr i = minZombiePage; i <= maxZombiePage; i++)
{
if (IsMyZombiePage(i))
{
UIntPtr startPage = i;
UIntPtr endPage = startPage;
do
{
endPage++;
} while (IsMyZombiePage(endPage));
InteriorPtrTable.ClearFirst(startPage, endPage);
if (GC.remsetType == RemSetType.Cards)
{
OffsetTable.ClearLast(PageTable.PageAddr(startPage),
PageTable.PageAddr(endPage) - 1);
}
if (!releasePages)
{
// Don't need to worry about giving the pages back
// Zero out the memory for reuse
UIntPtr pageCount = endPage - startPage;
PageManager.ReleaseUnusedPages(startPage,
pageCount,
false);
}
else if (reservePages > UIntPtr.Zero)
{
// Keep sufficient pages for the new nursery
UIntPtr pageCount = endPage - startPage;
if (pageCount > reservePages)
{
// Zero out the memory for reuse
PageManager.ReleaseUnusedPages(startPage,
reservePages,
false);
startPage += reservePages;
PageManager.FreePageRange(startPage, endPage);
reservePages = UIntPtr.Zero;
}
else
{
// Zero out the memory for reuse
PageManager.ReleaseUnusedPages(startPage,
pageCount,
false);
reservePages = reservePages - pageCount;
}
}
else
{
PageManager.FreePageRange(startPage, endPage);
}
i = endPage - 1;
}
}
}
private unsafe void FindDestinationArea(ref UIntPtr destPage,
ref UIntPtr destCursor,
ref UIntPtr destLimit,
UIntPtr objectSize,
PageType destGeneration)
{
VTable.Assert(IsValidGeneration((int)destGeneration));
UIntPtr cursorPage = PageTable.Page(destCursor);
UIntPtr limitPage = PageTable.Page(destLimit);
UIntPtr pageAddr = PageTable.PagePad(destCursor);
UIntPtr testPage = limitPage;
UIntPtr endTestPage = PageTable.PageCount(destCursor + objectSize);
if (destCursor > UIntPtr.Zero &&
IsMyZombiePage(PageTable.Page(destCursor - 1)))
{
VTable.Assert(destPage == limitPage);
while (IsMyZombiePage(testPage) ||
(testPage < endTestPage &&
(PageTable.IsUnusedPage(testPage))))
{
testPage++;
}
if (testPage >= endTestPage)
{
// We can expand the current region
endTestPage = testPage;
VTable.Assert(PageTable.PageAligned(destLimit));
InteriorPtrTable.ClearFirst(limitPage, testPage);
if (GC.remsetType == RemSetType.Cards)
{
OffsetTable.ClearLast(PageTable.PageAddr(limitPage),
PageTable.PageAddr(testPage) - 1);
}
while (limitPage != endTestPage)
{
VTable.Assert(PageTable.IsUnusedPage(destPage));
do
{
destPage++;
} while (destPage < endTestPage &&
PageTable.IsUnusedPage(destPage));
bool fCleanPages = true;
bool status =
PageManager.TryReserveUnusedPages(null, limitPage,
destPage - limitPage,
nurseryGeneration,
ref fCleanPages);
VTable.Assert(status);
MakeZombiePages(limitPage, destPage - limitPage,
destGeneration);
while (destPage < endTestPage &&
IsMyZombiePage(destPage))
{
destPage++;
}
limitPage = destPage;
}
destLimit = PageTable.PageAddr(limitPage);
return;
}
}
if (destCursor != pageAddr)
{
cursorPage++;
}
if (cursorPage != limitPage)
{
this.RegisterSkippedPages(cursorPage, limitPage);
}
// Find new region big enough to contain object
UIntPtr neededPages = PageTable.PageCount(objectSize);
UIntPtr prefixPage;
while (true)
{
do
{
destPage++;
} while (!IsMyZombiePage(destPage));
cursorPage = destPage;
prefixPage = cursorPage;
do
{
destPage++;
} while (IsMyZombiePage(destPage));
limitPage = destPage;
if (neededPages <= limitPage - cursorPage)
{
break;
}
// Check for following unused pages
endTestPage = cursorPage + neededPages;
VTable.Assert(endTestPage <= PageTable.pageTableCount);
while (destPage < endTestPage &&
(PageTable.IsUnusedPage(destPage) ||
(IsMyZombiePage(destPage))))
{
destPage++;
}
if (destPage == endTestPage)
{
break;
}
// Check for preceding unused pages
if (destPage >= neededPages)
{
endTestPage = destPage - neededPages;
prefixPage = cursorPage - 1;
while (prefixPage >= UIntPtr.Zero &&
PageTable.IsUnusedPage(prefixPage))
{
prefixPage--;
}
prefixPage++;
if (prefixPage == endTestPage)
{
break;
}
}
// Register any skipped regions of pages
this.RegisterSkippedPages(cursorPage, limitPage);
while (limitPage < destPage)
{
VTable.Assert(PageTable.IsUnusedPage(limitPage));
do
{
limitPage++;
} while (limitPage < destPage &&
PageTable.IsUnusedPage(limitPage));
cursorPage = limitPage;
while (limitPage < destPage && IsMyZombiePage(limitPage))
{
limitPage++;
}
if (cursorPage != limitPage)
{
this.RegisterSkippedPages(cursorPage, limitPage);
}
}
}
// We found an area big enough. Commit the pre- and
// postfix areas of unused pages
if (prefixPage != cursorPage)
{
bool fCleanPages = true;
bool status =
PageManager.TryReserveUnusedPages(null, prefixPage,
cursorPage - prefixPage,
nurseryGeneration,
ref fCleanPages);
VTable.Assert(status);
MakeZombiePages(prefixPage, cursorPage - prefixPage,
destGeneration);
}
while (destPage != limitPage)
{
// Mark the region of unused pages as fromspace
UIntPtr unusedPage = limitPage;
VTable.Assert(PageTable.IsUnusedPage(unusedPage));
do
{
unusedPage++;
} while (unusedPage < destPage &&
PageTable.IsUnusedPage(unusedPage));
bool fCleanPages = true;
bool status =
PageManager.TryReserveUnusedPages(null, limitPage,
unusedPage - limitPage,
nurseryGeneration,
ref fCleanPages);
VTable.Assert(status);
MakeZombiePages(limitPage, unusedPage - limitPage,
destGeneration);
// Skip any sections of pages already marked as fromspace
limitPage = unusedPage;
while (limitPage < destPage && IsMyZombiePage(limitPage))
{
limitPage++;
}
}
destCursor = PageTable.PageAddr(prefixPage);
destLimit = PageTable.PageAddr(limitPage);
// Take ownership of the new pages
InteriorPtrTable.ClearFirst(prefixPage, limitPage);
InteriorPtrTable.SetFirst(destCursor + PreHeader.Size);
if (GC.remsetType == RemSetType.Cards)
{
OffsetTable.ClearLast(PageTable.PageAddr(prefixPage),
PageTable.PageAddr(limitPage) - 1);
}
}
private static void CleanPageTail(UIntPtr postPinnedAddr)
{
if (!PageTable.PageAligned(postPinnedAddr))
{
// If postPinnedAddr points to the first object on its page,
// then we are removing all objects (specifically the part
// of the object that the InteriorPtrTable tracks, the
// vtables) from the page, so we should clear the page's
// entry in the InteriorPtrTable.
UIntPtr page = PageTable.Page(postPinnedAddr);
UIntPtr firstObjPtr = InteriorPtrTable.First(page);
if (firstObjPtr > postPinnedAddr)
{
VTable.Assert
(firstObjPtr - PreHeader.Size >= postPinnedAddr,
"postPinnedAddr should not point to the "
+ "interior of an object (1)");
InteriorPtrTable.ClearFirst(page);
}
else if (!BumpAllocator.IsUnusedSpace(firstObjPtr))
{
UIntPtr firstObjSize =
InteriorPtrTable.ObjectSize(firstObjPtr);
VTable.Assert
(firstObjPtr + firstObjSize - PreHeader.Size
<= postPinnedAddr,
"postPinnedAddr should not point to the "
+ "interior of an object (2)");
}
UIntPtr byteCount = PageTable.PagePad(postPinnedAddr)
- postPinnedAddr;
Util.MemClear(postPinnedAddr, byteCount);
BumpAllocator.WriteUnusedMarker(postPinnedAddr);
if (GC.remsetType == RemSetType.Cards && byteCount > 0)
{
UIntPtr firstCard = CardTable.CardNo(postPinnedAddr);
UIntPtr lastCard =
CardTable.CardNo(postPinnedAddr + byteCount - 1);
if (!OffsetTable.NoObjectPtrToTheCard(firstCard))
{
UIntPtr offset = OffsetTable.GetOffset(firstCard);
UIntPtr objPtr =
CardTable.CardAddr(firstCard) + offset;
UIntPtr size = OffsetTable.ObjectSize(objPtr);
VTable.Assert
((objPtr + size - PreHeader.Size
<= postPinnedAddr) ||
(objPtr >= postPinnedAddr),
"Object should be totally "
+ "above or below postPinnedAddr");
if (objPtr >= postPinnedAddr)
{
OffsetTable.ClearCards(firstCard, firstCard);
}
}
OffsetTable.ClearCards(firstCard + 1, lastCard);
}
}
}
internal void CleanPinnedPages()
{
if (pinnedPageList == null || pinnedPageList.Count == 0)
{
return;
}
int pageIndex = 0;
int limit = pinnedPageList.Count;
UIntPtr lastPostPinnedAddr = UIntPtr.Zero;
while (pageIndex < limit)
{
UIntPtr startPage = (UIntPtr)pinnedPageList[pageIndex];
UIntPtr endPage = startPage + 1;
pageIndex++;
while (pageIndex < limit &&
(UIntPtr)pinnedPageList[pageIndex] == endPage)
{
pageIndex++;
endPage++;
}
// Zero out the area between the start of the page and
// the first object on the page
UIntPtr firstObjectAddr = FirstPinnedObjectAddr(startPage);
UIntPtr firstAddr = firstObjectAddr - PreHeader.Size;
UIntPtr trashAddr = PageTable.PageAddr(startPage);
if (firstAddr < trashAddr)
{
// The first object "spills" into the previous page,
// presumably by no more than HEADER_BYTES bytes
VTable.Assert(
PageTable.Page(firstAddr) == startPage - 1,
"Semispace:RegisterPinnedReference:3");
// Prepare to zero the preceding page unless it also
// had pinned data on it
trashAddr = PageTable.PageAddr(startPage - 1);
InteriorPtrTable.ClearFirst(startPage - 1);
if (trashAddr >= lastPostPinnedAddr)
{
// Need to mark the spilled-onto page live to
// keep the spilled data around
PageType fromSpaceType =
PageTable.Type(startPage - 1);
VTable.Assert(
PageTable.IsZombiePage(fromSpaceType),
"Semispace:RegisterPinnedReference:4");
PageType toSpaceType =
PageTable.ZombieToLive(fromSpaceType);
PageTable.SetType(startPage - 1, toSpaceType);
}
}
// If lastPostPinnedAddr is on the page that trashAddr
// starts, pinned data from the last run of pinned pages
// and pinned data from this run of pinned data are on the
// same page, so just write alignment tokens from
// lastPostPinnedAddr to the first pinned object.
// Otherwise, write an unused marker at lastPostPinnedAddr
// since the rest of its page must be copied or dead.
if (trashAddr < lastPostPinnedAddr)
{
trashAddr = lastPostPinnedAddr;
}
else
{
CleanPageTail(lastPostPinnedAddr);
}
if (GC.remsetType == RemSetType.Cards &&
trashAddr < firstAddr)
{
UIntPtr firstCard = CardTable.CardNo(trashAddr);
UIntPtr lastCard = CardTable.CardNo(firstAddr - 1);
if (!OffsetTable.NoObjectPtrToTheCard(firstCard))
{
UIntPtr offset = OffsetTable.GetOffset(firstCard);
UIntPtr objPtr =
CardTable.CardAddr(firstCard) + offset;
UIntPtr size = OffsetTable.ObjectSize(objPtr);
VTable.Assert
((objPtr + size - PreHeader.Size <= trashAddr) ||
(objPtr >= trashAddr),
"Object should be totally "
+ "above or below trashAddr");
if (objPtr >= trashAddr)
{
// The offset in this card needs to be updated
OffsetTable.ClearCards(firstCard, firstCard);
}
}
OffsetTable.ClearCards(firstCard + 1, lastCard - 1);
if (lastCard != CardTable.CardNo(firstObjectAddr))
{
OffsetTable.ClearCards(lastCard, lastCard);
}
else
{
VTable.Assert(OffsetTable.GetOffset(lastCard)
>= (firstObjectAddr
- CardTable.CardAddr(lastCard)),
"wrong offset");
}
}
{
// trashAddr should go back at most one page.
UIntPtr trashPage = PageTable.Page(trashAddr);
UIntPtr firstObjectAddrPage =
PageTable.Page(firstObjectAddr);
VTable.Assert((trashPage == firstObjectAddrPage - 1) ||
(trashPage == firstObjectAddrPage));
}
// If the InteriorPtrTable already had a value, then this is
// redundant, but if the call to First above has to compute
// the value, then (since it won't store it in the table) we
// should store it. Why? At this point the previous page
// would be "connected" to this one. After this collection
// the previous page will be unused or re-used and unrelated
// to this page and subsequent calls to First would then
// rely on it making the leap between unrelated pages.
InteriorPtrTable.SetFirst(firstObjectAddr);
while (trashAddr < firstAddr)
{
Allocator.WriteAlignment(trashAddr);
trashAddr += UIntPtr.Size;
}
// Zero out the area between the last whole object on
// the last page and the end of the last page
UIntPtr pastAddr = PostPinnedObjectAddr(endPage);
UIntPtr newEndPage =
PageTable.Page(PageTable.PagePad(pastAddr));
while (endPage < newEndPage)
{
// The last object spills into the next page(s), so
// mark those page(s) live
PageType fromPageType = PageTable.Type(endPage);
if (PageTable.IsZombiePage(fromPageType))
{
PageType toSpaceType =
PageTable.ZombieToLive(fromPageType);
PageTable.SetType(endPage, toSpaceType);
}
else
{
// final page might be live already because
// something else on it was pinned.
// pageIndex has already been incremented,
// so it points to the start of the next
// set of contiguous pages
VTable.Assert(
PageTable.IsLiveGcPage(fromPageType) &&
pageIndex < limit &&
endPage ==
(UIntPtr)pinnedPageList[pageIndex],
"Semispace:RegisterPinnedReference:5");
}
++endPage;
}
lastPostPinnedAddr = pastAddr;
}
CleanPageTail(lastPostPinnedAddr);
pinnedPageList = null;
comparer = null;
}
private UIntPtr ExtendAlloc(UIntPtr bytes, uint alignment,
Thread currentThread)
{
if (this.reserveLimit == UIntPtr.Zero)
{
return(UIntPtr.Zero);
}
#if SINGULARITY_KERNEL
Kernel.Waypoint(700);
#endif
UIntPtr neededBytes =
bytes + // Bytes required for object +
alignment - UIntPtr.Size - // worst case alignment overhead +
(this.reserveLimit - this.allocPtr); // bytes already available
UIntPtr paddedNeed = PageTable.PagePad(neededBytes);
UIntPtr pageCount = PageTable.PageCount(paddedNeed);
UIntPtr startPage = PageTable.Page(this.reserveLimit);
bool fCleanPages = CLEAR_POOL_PAGES();
bool gotPages =
PageManager.TryReserveUnusedPages(currentThread, startPage,
pageCount, this.pageType,
ref fCleanPages);
if (!gotPages)
{
// We can't indiscriminately ask for more memory if we have
// unused pages already available.
return(UIntPtr.Zero);
}
if (this.reserveLimit == UIntPtr.Zero)
{
// A collection occurred, so there is no region to extend
PageManager.ReleaseUnusedPages(startPage, pageCount,
fCleanPages);
return(UIntPtr.Zero);
}
BaseCollector.IncrementNewBytesSinceGC(paddedNeed);
this.allocNew = this.reserveLimit;
// Pad alignment space if necessary. NB: a prior call to
// AllocateFast may have started generating alignment tokens,
// but we may need to finish the job here if the residual space
// was insufficient for a multi-word alignment.
UIntPtr oldReserveLimit = this.reserveLimit;
this.reserveLimit += paddedNeed;
this.allocPtr =
Allocator.AlignedAllocationPtr(this.allocPtr,
this.reserveLimit,
alignment);
if (this.zeroedLimit < this.allocPtr)
{
this.zeroedLimit = this.allocPtr;
}
UIntPtr objectAddr = this.allocPtr + PreHeader.Size;
this.allocPtr += bytes;
if (fCleanPages)
{
if (this.zeroedLimit < oldReserveLimit)
{
Util.MemClear(this.zeroedLimit,
oldReserveLimit - this.zeroedLimit);
}
this.zeroedLimit = this.reserveLimit;
}
else
{
Util.MemClear(this.zeroedLimit,
this.allocPtr - this.zeroedLimit);
this.zeroedLimit = this.allocPtr;
}
VTable.Assert(this.allocPtr <= this.zeroedLimit);
VTable.Assert(PageTable.PageAligned(this.reserveLimit));
if (objectAddr >= oldReserveLimit)
{
// Object is first on new page
InteriorPtrTable.SetFirst(objectAddr);
}
else if (objectAddr + bytes < this.reserveLimit)
{
// The object does not end on new limit
// N.B. The next object may not be allocated at exactly
// (objectAddr + bytes) due to alignment considerations. It
// also might not ever be allocated. These cases are handled
// by InteriorPtrTable.First skipping over alignment tokens
// and callers of First watching out for unused space tokens.
InteriorPtrTable.SetFirst(objectAddr + bytes);
}
// We know an object is located as the last one in a page
// when it extends through the page to the next.
// Otherwise, it is totally before or below the page, and
// we are not sure whether it is the last object or not.
// So record only such an object for the last card in that
// page. Many objects may have been omitted due to
// this coarse-grain recording. But we should be able
// to incrementally update the offset table and find them.
// I believe this is a better choice than simply recording
// any object to the offset table, because most objects
// may just die and need not to record.
#if !SINGULARITY || SEMISPACE_COLLECTOR || ADAPTIVE_COPYING_COLLECTOR || SLIDING_COLLECTOR
if (GC.remsetType == RemSetType.Cards)
{
if (objectAddr < oldReserveLimit &&
allocPtr + bytes > oldReserveLimit)
{
#if DONT_RECORD_OBJALLOC_IN_OFFSETTABLE
#else
OffsetTable.SetLast(objectAddr);
#endif
}
}
#endif
#if SINGULARITY_KERNEL
Kernel.Waypoint(701);
#endif
return(objectAddr);
}
