diff options
Diffstat (limited to 'src/qml/memory/qv4mm.cpp')
| -rw-r--r-- | src/qml/memory/qv4mm.cpp | 331 |
1 files changed, 277 insertions, 54 deletions
diff --git a/src/qml/memory/qv4mm.cpp b/src/qml/memory/qv4mm.cpp index a829e902fb..c025dd09a4 100644 --- a/src/qml/memory/qv4mm.cpp +++ b/src/qml/memory/qv4mm.cpp @@ -60,7 +60,11 @@ #include "qv4alloca_p.h" #include "qv4profiling_p.h" -#define MM_DEBUG 0 +//#define MM_STATS + +#if !defined(MM_STATS) && !defined(QT_NO_DEBUG) +#define MM_STATS +#endif #if MM_DEBUG #define DEBUG qDebug() << "MM:" @@ -113,14 +117,16 @@ struct MemorySegment { pageReservation = PageReservation::reserve(size, OSAllocator::JSGCHeapPages); base = reinterpret_cast<Chunk *>((reinterpret_cast<quintptr>(pageReservation.base()) + Chunk::ChunkSize - 1) & ~(Chunk::ChunkSize - 1)); nChunks = NumChunks; - if (base != pageReservation.base()) + availableBytes = size - (reinterpret_cast<quintptr>(base) - reinterpret_cast<quintptr>(pageReservation.base())); + if (availableBytes < SegmentSize) --nChunks; } MemorySegment(MemorySegment &&other) { qSwap(pageReservation, other.pageReservation); qSwap(base, other.base); - qSwap(nChunks, other.nChunks); qSwap(allocatedMap, other.allocatedMap); + qSwap(availableBytes, other.availableBytes); + qSwap(nChunks, other.nChunks); } ~MemorySegment() { @@ -150,7 +156,7 @@ struct MemorySegment { void free(Chunk *chunk, size_t size) { DEBUG << "freeing chunk" << chunk; size_t index = static_cast<size_t>(chunk - base); - size_t end = index + (size - 1)/Chunk::ChunkSize + 1; + size_t end = qMin(static_cast<size_t>(NumChunks), index + (size - 1)/Chunk::ChunkSize + 1); while (index < end) { Q_ASSERT(testBit(index)); clearBit(index); @@ -169,11 +175,19 @@ struct MemorySegment { PageReservation pageReservation; Chunk *base = 0; quint64 allocatedMap = 0; + size_t availableBytes = 0; uint nChunks = 0; }; Chunk *MemorySegment::allocate(size_t size) { + if (!allocatedMap && size >= SegmentSize) { + // chunk allocated for one huge allocation + Q_ASSERT(availableBytes >= size); + pageReservation.commit(base, size); + allocatedMap = ~static_cast<quintptr>(0); + return base; + } size_t requiredChunks = (size + sizeof(Chunk) - 1)/sizeof(Chunk); uint sequence = 0; Chunk *candidate = 0; @@ -251,7 +265,9 @@ void Chunk::sweep() // DEBUG << "sweeping chunk" << this << (*freeList); HeapItem *o = realBase(); for (uint i = 0; i < Chunk::EntriesInBitmap; ++i) { +#if WRITEBARRIER(none) Q_ASSERT((grayBitmap[i] | blackBitmap[i]) == blackBitmap[i]); // check that we don't have gray only objects +#endif quintptr toFree = objectBitmap[i] ^ blackBitmap[i]; Q_ASSERT((toFree & objectBitmap[i]) == toFree); // check all black objects are marked as being used quintptr e = extendsBitmap[i]; @@ -280,7 +296,7 @@ void Chunk::sweep() } } objectBitmap[i] = blackBitmap[i]; - blackBitmap[i] = 0; + grayBitmap[i] = 0; extendsBitmap[i] = e; o += Chunk::Bits; } @@ -319,13 +335,56 @@ void Chunk::freeAll() } } objectBitmap[i] = 0; - blackBitmap[i] = 0; + grayBitmap[i] = 0; extendsBitmap[i] = e; o += Chunk::Bits; } // DEBUG << "swept chunk" << this << "freed" << slotsFreed << "slots."; } +void Chunk::resetBlackBits() +{ + memset(blackBitmap, 0, sizeof(blackBitmap)); +} + +#ifdef MM_STATS +static uint nGrayItems = 0; +#endif + +void Chunk::collectGrayItems(ExecutionEngine *engine) +{ + // DEBUG << "sweeping chunk" << this << (*freeList); + HeapItem *o = realBase(); + for (uint i = 0; i < Chunk::EntriesInBitmap; ++i) { +#if WRITEBARRIER(none) + Q_ASSERT((grayBitmap[i] | blackBitmap[i]) == blackBitmap[i]); // check that we don't have gray only objects +#endif + quintptr toMark = blackBitmap[i] & grayBitmap[i]; // correct for a Steele type barrier + Q_ASSERT((toMark & objectBitmap[i]) == toMark); // check all black objects are marked as being used + // DEBUG << hex << " index=" << i << toFree; + while (toMark) { + uint index = qCountTrailingZeroBits(toMark); + quintptr bit = (static_cast<quintptr>(1) << index); + + toMark ^= bit; // mask out marked slot + // DEBUG << " index" << hex << index << toFree; + + HeapItem *itemToFree = o + index; + Heap::Base *b = *itemToFree; + Q_ASSERT(b->inUse()); + engine->pushForGC(b); +#ifdef MM_STATS + ++nGrayItems; +// qDebug() << "adding gray item" << b << "to mark stack"; +#endif + } + grayBitmap[i] = 0; + o += Chunk::Bits; + } + // DEBUG << "swept chunk" << this << "freed" << slotsFreed << "slots."; + +} + void Chunk::sortIntoBins(HeapItem **bins, uint nBins) { // qDebug() << "sortIntoBins:"; @@ -335,7 +394,7 @@ void Chunk::sortIntoBins(HeapItem **bins, uint nBins) #else const int start = 1; #endif -#ifndef QT_NO_DEBUG +#ifdef MM_STATS uint freeSlots = 0; uint allocatedSlots = 0; #endif @@ -345,7 +404,7 @@ void Chunk::sortIntoBins(HeapItem **bins, uint nBins) if (!i) usedSlots |= (static_cast<quintptr>(1) << (HeaderSize/SlotSize)) - 1; #endif -#ifndef QT_NO_DEBUG +#ifdef MM_STATS allocatedSlots += qPopulationCount(usedSlots); // qDebug() << hex << " i=" << i << "used=" << usedSlots; #endif @@ -362,7 +421,7 @@ void Chunk::sortIntoBins(HeapItem **bins, uint nBins) break; } usedSlots = (objectBitmap[i]|extendsBitmap[i]); -#ifndef QT_NO_DEBUG +#ifdef MM_STATS allocatedSlots += qPopulationCount(usedSlots); // qDebug() << hex << " i=" << i << "used=" << usedSlots; #endif @@ -373,7 +432,7 @@ void Chunk::sortIntoBins(HeapItem **bins, uint nBins) usedSlots |= (quintptr(1) << index) - 1; uint freeEnd = i*Bits + index; uint nSlots = freeEnd - freeStart; -#ifndef QT_NO_DEBUG +#ifdef MM_STATS // qDebug() << hex << " got free slots from" << freeStart << "to" << freeEnd << "n=" << nSlots << "usedSlots=" << usedSlots; freeSlots += nSlots; #endif @@ -384,7 +443,7 @@ void Chunk::sortIntoBins(HeapItem **bins, uint nBins) bins[bin] = freeItem; } } -#ifndef QT_NO_DEBUG +#ifdef MM_STATS Q_ASSERT(freeSlots + allocatedSlots == (EntriesInBitmap - start) * 8 * sizeof(quintptr)); #endif } @@ -555,6 +614,19 @@ void BlockAllocator::freeAll() } } +void BlockAllocator::resetBlackBits() +{ + for (auto c : chunks) + c->resetBlackBits(); +} + +void BlockAllocator::collectGrayItems(ExecutionEngine *engine) +{ + for (auto c : chunks) + c->collectGrayItems(engine); + +} + #if MM_DEBUG void BlockAllocator::stats() { DEBUG << "MM stats:"; @@ -607,7 +679,6 @@ static void freeHugeChunk(ChunkAllocator *chunkAllocator, const HugeItemAllocato void HugeItemAllocator::sweep() { auto isBlack = [this] (const HugeChunk &c) { bool b = c.chunk->first()->isBlack(); - Chunk::clearBit(c.chunk->blackBitmap, c.chunk->first() - c.chunk->realBase()); if (!b) freeHugeChunk(chunkAllocator, c); return !b; @@ -617,6 +688,24 @@ void HugeItemAllocator::sweep() { chunks.erase(newEnd, chunks.end()); } +void HugeItemAllocator::resetBlackBits() +{ + for (auto c : chunks) + Chunk::clearBit(c.chunk->blackBitmap, c.chunk->first() - c.chunk->realBase()); +} + +void HugeItemAllocator::collectGrayItems(ExecutionEngine *engine) +{ + for (auto c : chunks) + // Correct for a Steele type barrier + if (Chunk::testBit(c.chunk->blackBitmap, c.chunk->first() - c.chunk->realBase()) && + Chunk::testBit(c.chunk->grayBitmap, c.chunk->first() - c.chunk->realBase())) { + HeapItem *i = c.chunk->first(); + Heap::Base *b = *i; + b->mark(engine); + } +} + void HugeItemAllocator::freeAll() { for (auto &c : chunks) { @@ -642,15 +731,17 @@ MemoryManager::MemoryManager(ExecutionEngine *engine) #endif } -#ifndef QT_NO_DEBUG +#ifdef MM_STATS +static int allocationCount = 0; static size_t lastAllocRequestedSlots = 0; #endif Heap::Base *MemoryManager::allocString(std::size_t unmanagedSize) { const size_t stringSize = align(sizeof(Heap::String)); -#ifndef QT_NO_DEBUG +#ifdef MM_STATS lastAllocRequestedSlots = stringSize >> Chunk::SlotSizeShift; + ++allocationCount; #endif bool didGCRun = false; @@ -661,7 +752,8 @@ Heap::Base *MemoryManager::allocString(std::size_t unmanagedSize) unmanagedHeapSize += unmanagedSize; if (unmanagedHeapSize > unmanagedHeapSizeGCLimit) { - runGC(); + if (!didGCRun) + runGC(); if (3*unmanagedHeapSizeGCLimit <= 4*unmanagedHeapSize) // more than 75% full, raise limit @@ -679,14 +771,16 @@ Heap::Base *MemoryManager::allocString(std::size_t unmanagedSize) m = blockAllocator.allocate(stringSize, true); } +// qDebug() << "allocated string" << m; memset(m, 0, stringSize); return *m; } Heap::Base *MemoryManager::allocData(std::size_t size) { -#ifndef QT_NO_DEBUG +#ifdef MM_STATS lastAllocRequestedSlots = size >> Chunk::SlotSizeShift; + ++allocationCount; #endif bool didRunGC = false; @@ -703,8 +797,11 @@ Heap::Base *MemoryManager::allocData(std::size_t size) // qDebug() << "unmanagedHeapSize:" << unmanagedHeapSize << "limit:" << unmanagedHeapSizeGCLimit << "unmanagedSize:" << unmanagedSize; - if (size > Chunk::DataSize) - return *hugeItemAllocator.allocate(size); + if (size > Chunk::DataSize) { + HeapItem *h = hugeItemAllocator.allocate(size); +// qDebug() << "allocating huge item" << h; + return *h; + } HeapItem *m = blockAllocator.allocate(size); if (!m) { @@ -714,39 +811,92 @@ Heap::Base *MemoryManager::allocData(std::size_t size) } memset(m, 0, size); +// qDebug() << "allocating data" << m; return *m; } Heap::Object *MemoryManager::allocObjectWithMemberData(std::size_t size, uint nMembers) { - Heap::Object *o = static_cast<Heap::Object *>(allocData(size)); - - // ### Could optimize this and allocate both in one go through the block allocator - if (nMembers) { + Heap::Object *o; + if (!nMembers) { + o = static_cast<Heap::Object *>(allocData(size)); + } else { + // Allocate both in one go through the block allocator std::size_t memberSize = align(sizeof(Heap::MemberData) + (nMembers - 1)*sizeof(Value)); -// qDebug() << "allocating member data for" << o << nMembers << memberSize; - Heap::Base *m; - if (memberSize > Chunk::DataSize) - m = *hugeItemAllocator.allocate(memberSize); - else - m = *blockAllocator.allocate(memberSize, true); - memset(m, 0, memberSize); - o->memberData = static_cast<Heap::MemberData *>(m); - o->memberData->setVtable(MemberData::staticVTable()); - o->memberData->size = static_cast<uint>((memberSize - sizeof(Heap::MemberData) + sizeof(Value))/sizeof(Value)); - o->memberData->init(); + size_t totalSize = size + memberSize; + Heap::MemberData *m; + if (totalSize > Chunk::DataSize) { + o = static_cast<Heap::Object *>(allocData(size)); + m = hugeItemAllocator.allocate(memberSize)->as<Heap::MemberData>(); + } else { + HeapItem *mh = reinterpret_cast<HeapItem *>(allocData(totalSize)); + Heap::Base *b = *mh; + o = static_cast<Heap::Object *>(b); + mh += (size >> Chunk::SlotSizeShift); + m = mh->as<Heap::MemberData>(); + Chunk *c = mh->chunk(); + size_t index = mh - c->realBase(); + Chunk::setBit(c->objectBitmap, index); + Chunk::clearBit(c->extendsBitmap, index); + } + o->memberData.set(engine, m); + m->setVtable(MemberData::staticVTable()); + m->values.alloc = static_cast<uint>((memberSize - sizeof(Heap::MemberData) + sizeof(Value))/sizeof(Value)); + m->values.size = o->memberData->values.alloc; + m->init(); // qDebug() << " got" << o->memberData << o->memberData->size; } +// qDebug() << "allocating object with memberData" << o << o->memberData.operator->(); return o; } -static void drainMarkStack(QV4::ExecutionEngine *engine, Value *markBase) +static uint markStackSize = 0; + +void MemoryManager::drainMarkStack(Value *markBase) { while (engine->jsStackTop > markBase) { Heap::Base *h = engine->popForGC(); + ++markStackSize; Q_ASSERT(h); // at this point we should only have Heap::Base objects in this area on the stack. If not, weird things might happen. - Q_ASSERT (h->vtable()->markObjects); - h->vtable()->markObjects(h, engine); + if (h->vtable()->markObjects) + h->vtable()->markObjects(h, engine); + if (quint64 m = h->vtable()->markTable) { +// qDebug() << "using mark table:" << hex << m << "for" << h; + void **mem = reinterpret_cast<void **>(h); + while (m) { + MarkFlags mark = static_cast<MarkFlags>(m & 3); + switch (mark) { + case Mark_NoMark: + break; + case Mark_Value: +// qDebug() << "marking value at " << mem; + reinterpret_cast<Value *>(mem)->mark(engine); + break; + case Mark_Pointer: { +// qDebug() << "marking pointer at " << mem; + Heap::Base *p = *reinterpret_cast<Heap::Base **>(mem); + if (p) + p->mark(engine); + break; + } + case Mark_ValueArray: { + Q_ASSERT(m == Mark_ValueArray); +// qDebug() << "marking Value Array at offset" << hex << (mem - reinterpret_cast<void **>(h)); + ValueArray<0> *a = reinterpret_cast<ValueArray<0> *>(mem); + Value *v = a->values; + const Value *end = v + a->alloc; + while (v < end) { + v->mark(engine); + ++v; + } + break; + } + } + + m >>= 2; + ++mem; + } + } } } @@ -754,12 +904,28 @@ void MemoryManager::mark() { Value *markBase = engine->jsStackTop; - engine->markObjects(); + markStackSize = 0; + + if (nextGCIsIncremental) { + // need to collect all gray items and push them onto the mark stack + blockAllocator.collectGrayItems(engine); + hugeItemAllocator.collectGrayItems(engine); + } + +// qDebug() << ">>>> Mark phase:"; +// qDebug() << " mark stack after gray items" << (engine->jsStackTop - markBase); + + engine->markObjects(nextGCIsIncremental); + +// qDebug() << " mark stack after engine->mark" << (engine->jsStackTop - markBase); collectFromJSStack(); +// qDebug() << " mark stack after js stack collect" << (engine->jsStackTop - markBase); m_persistentValues->mark(engine); +// qDebug() << " mark stack after persistants" << (engine->jsStackTop - markBase); + // Preserve QObject ownership rules within JavaScript: A parent with c++ ownership // keeps all of its children alive in JavaScript. @@ -788,14 +954,20 @@ void MemoryManager::mark() qobjectWrapper->mark(engine); if (engine->jsStackTop >= engine->jsStackLimit) - drainMarkStack(engine, markBase); + drainMarkStack(markBase); } - drainMarkStack(engine, markBase); + drainMarkStack(markBase); } void MemoryManager::sweep(bool lastSweep) { + if (lastSweep && nextGCIsIncremental) { + // ensure we properly clean up on destruction even if the GC is in incremental mode + blockAllocator.resetBlackBits(); + hugeItemAllocator.resetBlackBits(); + } + for (PersistentValueStorage::Iterator it = m_weakValues->begin(); it != m_weakValues->end(); ++it) { Managed *m = (*it).managed(); if (!m || m->markBit()) @@ -848,41 +1020,48 @@ void MemoryManager::sweep(bool lastSweep) bool MemoryManager::shouldRunGC() const { size_t total = blockAllocator.totalSlots(); - size_t usedSlots = blockAllocator.usedSlotsAfterLastSweep; - if (total > MinSlotsGCLimit && usedSlots * GCOverallocation < total * 100) + if (total > MinSlotsGCLimit && usedSlotsAfterLastFullSweep * GCOverallocation < total * 100) return true; return false; } size_t dumpBins(BlockAllocator *b, bool printOutput = true) { - size_t totalFragmentedSlots = 0; + size_t totalSlotMem = 0; if (printOutput) - qDebug() << "Fragmentation map:"; + qDebug() << "Slot map:"; for (uint i = 0; i < BlockAllocator::NumBins; ++i) { uint nEntries = 0; HeapItem *h = b->freeBins[i]; while (h) { ++nEntries; - totalFragmentedSlots += h->freeData.availableSlots; + totalSlotMem += h->freeData.availableSlots; h = h->freeData.next; } if (printOutput) qDebug() << " number of entries in slot" << i << ":" << nEntries; } if (printOutput) - qDebug() << " total mem in bins" << totalFragmentedSlots*Chunk::SlotSize; - return totalFragmentedSlots*Chunk::SlotSize; + qDebug() << " total mem in bins" << totalSlotMem*Chunk::SlotSize; + return totalSlotMem*Chunk::SlotSize; } -void MemoryManager::runGC() +void MemoryManager::runGC(bool forceFullCollection) { if (gcBlocked) { // qDebug() << "Not running GC."; return; } + if (forceFullCollection) { + // do a full GC + blockAllocator.resetBlackBits(); + hugeItemAllocator.resetBlackBits(); + nextGCIsIncremental = false; + } + QScopedValueRollback<bool> gcBlocker(gcBlocked, true); +// qDebug() << "runGC"; if (!gcStats) { // uint oldUsed = allocator.usedMem(); @@ -897,21 +1076,29 @@ void MemoryManager::runGC() const size_t largeItemsBefore = getLargeItemsMem(); qDebug() << "========== GC =========="; -#ifndef QT_NO_DEBUG +#ifdef MM_STATS qDebug() << " Triggered by alloc request of" << lastAllocRequestedSlots << "slots."; + qDebug() << " Allocations since last GC" << allocationCount; + allocationCount = 0; #endif + qDebug() << "Incremental:" << nextGCIsIncremental; qDebug() << "Allocated" << totalMem << "bytes in" << blockAllocator.chunks.size() << "chunks"; qDebug() << "Fragmented memory before GC" << (totalMem - usedBefore); dumpBins(&blockAllocator); +#ifdef MM_STATS + nGrayItems = 0; +#endif + QElapsedTimer t; t.start(); mark(); - qint64 markTime = t.restart(); + qint64 markTime = t.nsecsElapsed()/1000; + t.restart(); sweep(); const size_t usedAfter = getUsedMem(); const size_t largeItemsAfter = getLargeItemsMem(); - qint64 sweepTime = t.elapsed(); + qint64 sweepTime = t.nsecsElapsed()/1000; if (triggeredByUnmanagedHeap) { qDebug() << "triggered by unmanaged heap:"; @@ -920,11 +1107,16 @@ void MemoryManager::runGC() qDebug() << " unmanaged heap limit:" << unmanagedHeapSizeGCLimit; } size_t memInBins = dumpBins(&blockAllocator); - qDebug() << "Marked object in" << markTime << "ms."; - qDebug() << "Sweeped object in" << sweepTime << "ms."; +#ifdef MM_STATS + if (nextGCIsIncremental) + qDebug() << " number of gray items:" << nGrayItems; +#endif + qDebug() << "Marked object in" << markTime << "us."; + qDebug() << " " << markStackSize << "objects marked"; + qDebug() << "Sweeped object in" << sweepTime << "us."; qDebug() << "Used memory before GC:" << usedBefore; - qDebug() << "Used memory after GC:" << usedAfter; - qDebug() << "Freed up bytes:" << (usedBefore - usedAfter); + qDebug() << "Used memory after GC :" << usedAfter; + qDebug() << "Freed up bytes :" << (usedBefore - usedAfter); size_t lost = blockAllocator.allocatedMem() - memInBins - usedAfter; if (lost) qDebug() << "!!!!!!!!!!!!!!!!!!!!! LOST MEM:" << lost << "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"; @@ -940,6 +1132,37 @@ void MemoryManager::runGC() // ensure we don't 'loose' any memory Q_ASSERT(blockAllocator.allocatedMem() == getUsedMem() + dumpBins(&blockAllocator, false)); } + + if (!nextGCIsIncremental) + usedSlotsAfterLastFullSweep = blockAllocator.usedSlotsAfterLastSweep; + +#if WRITEBARRIER(steele) + static int count = 0; + ++count; + if (aggressiveGC) { + nextGCIsIncremental = (count % 256); + } else { + size_t total = blockAllocator.totalSlots(); + size_t usedSlots = blockAllocator.usedSlotsAfterLastSweep; + if (!nextGCIsIncremental) { + // always try an incremental GC after a full one, unless there is anyway lots of memory pressure + nextGCIsIncremental = usedSlots * 4 < total * 3; + count = 0; + } else { + if (count > 16) + nextGCIsIncremental = false; + else + nextGCIsIncremental = usedSlots * 4 < total * 3; // less than 75% full + } + } +#else + nextGCIsIncremental = false; +#endif + if (!nextGCIsIncremental) { + // do a full GC + blockAllocator.resetBlackBits(); + hugeItemAllocator.resetBlackBits(); + } } size_t MemoryManager::getUsedMem() const |