Changeset 252452 in webkit for trunk/Source/JavaScriptCore/heap/IsoSubspacePerVM.cpp

Timestamp:

Nov 14, 2019, 1:37:12 AM (6 years ago)

Author:

[email protected]

Message:

[JSC] BlockDirectory's bits should be compact
​https://bugs.webkit.org/show_bug.cgi?id=204149

Reviewed by Robin Morisset.

Source/JavaScriptCore:

We start applying IsoSubspace to all JSCells. This means that IsoSubspace should be small enough,
so that we can hold many IsoSubspaces without considering about memory regression.

In this patch, we introduce several things to shrink sizeof(IsoSubspace) from 528 to 384.

1. Adjusting members to remove some paddings.
2. Remove m_heap field since this can be got from the caller easily.
3. Make MarkedSpace::heap() efficient: just doing pointer arithmetic.
4. Remove m_size field from IsoSubspace since BlockDirectory knows cellSize.
5. Introduce BlockDirectoryBits, which repalces 9 FastBitVector in BlockDirectory to this one class. Since all FastBitVector has the same size, we should not have a size field for each FastBitVector. We reuse FastBitVector's View mechanism to keep the same ergonomics while making BlockDirectoryBits much smaller. We put 9 uint32_t as Segment, and manage Vector<Segment> in this data structure. Since we touch several bits at the same time for the same block-index, this data structure is compact and efficient.

• CMakeLists.txt:
• JavaScriptCore.xcodeproj/project.pbxproj:
• heap/AlignedMemoryAllocator.cpp:

(JSC::AlignedMemoryAllocator::registerDirectory):

• heap/AlignedMemoryAllocator.h:
• heap/Allocator.h:
• heap/AllocatorInlines.h:

(JSC::Allocator::allocate const):

• heap/BlockDirectory.cpp:

(JSC::BlockDirectory::BlockDirectory):
(JSC::BlockDirectory::findEmptyBlockToSteal):
(JSC::BlockDirectory::findBlockForAllocation):
(JSC::BlockDirectory::tryAllocateBlock):
(JSC::BlockDirectory::addBlock):
(JSC::BlockDirectory::removeBlock):
(JSC::BlockDirectory::prepareForAllocation):
(JSC::BlockDirectory::beginMarkingForFullCollection):
(JSC::BlockDirectory::endMarking):
(JSC::BlockDirectory::snapshotUnsweptForEdenCollection):
(JSC::BlockDirectory::snapshotUnsweptForFullCollection):
(JSC::BlockDirectory::findBlockToSweep):
(JSC::BlockDirectory::sweep):
(JSC::BlockDirectory::shrink):
(JSC::BlockDirectory::assertNoUnswept):
(JSC::BlockDirectory::parallelNotEmptyBlockSource):
(JSC::BlockDirectory::dumpBits):

• heap/BlockDirectory.h:

(JSC::BlockDirectory::cellKind const):
(JSC::BlockDirectory::forEachBitVector):
(JSC::BlockDirectory::forEachBitVectorWithName):
(JSC::BlockDirectory::heap): Deleted.

• heap/BlockDirectoryBits.h: Added.

(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::BlockDirectoryBitVectorWordView):
(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::numBits const):
(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::word const):
(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::word):
(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::clearAll):
(JSC::BlockDirectoryBits::BlockDirectoryBitVectorWordView::view const):
(JSC::BlockDirectoryBits::numBits const):
(JSC::BlockDirectoryBits::resize):
(JSC::BlockDirectoryBits::forEachSegment):

• heap/BlockDirectoryInlines.h:

(JSC::BlockDirectory::forEachBlock):
(JSC::BlockDirectory::forEachNotEmptyBlock):

• heap/CompleteSubspace.cpp:

(JSC::CompleteSubspace::allocatorForSlow):
(JSC::CompleteSubspace::tryAllocateSlow):

• heap/CompleteSubspaceInlines.h:

(JSC::CompleteSubspace::allocateNonVirtual):

• heap/IsoCellSet.cpp:

(JSC::IsoCellSet::parallelNotEmptyMarkedBlockSource):

• heap/IsoCellSetInlines.h:

(JSC::IsoCellSet::forEachMarkedCell):

• heap/IsoSubspace.cpp:

(JSC::IsoSubspace::IsoSubspace):
(JSC::IsoSubspace::tryAllocateFromLowerTier):

• heap/IsoSubspace.h:

(JSC::IsoSubspace::cellSize):
(JSC::IsoSubspace::allocatorForNonVirtual):
(JSC::IsoSubspace::size const): Deleted.
(): Deleted.

• heap/IsoSubspaceInlines.h:

(JSC::IsoSubspace::allocateNonVirtual):

• heap/IsoSubspacePerVM.cpp:

(JSC::IsoSubspacePerVM::AutoremovingIsoSubspace::~AutoremovingIsoSubspace):

• heap/LocalAllocator.cpp:

(JSC::LocalAllocator::allocateSlowCase):
(JSC::LocalAllocator::doTestCollectionsIfNeeded):

• heap/LocalAllocator.h:
• heap/LocalAllocatorInlines.h:

(JSC::LocalAllocator::allocate):

• heap/MarkedBlock.cpp:

(JSC::MarkedBlock::Handle::dumpState):

• heap/MarkedSpace.cpp:

(JSC::MarkedSpace::MarkedSpace):
(JSC::MarkedSpace::sweepBlocks):
(JSC::MarkedSpace::prepareForAllocation):
(JSC::MarkedSpace::visitWeakSets):
(JSC::MarkedSpace::reapWeakSets):
(JSC::MarkedSpace::prepareForMarking):
(JSC::MarkedSpace::beginMarking):
(JSC::MarkedSpace::snapshotUnswept):

• heap/MarkedSpace.h:

(JSC::MarkedSpace::heap const): Deleted.

• heap/MarkedSpaceInlines.h:

(JSC::MarkedSpace::heap const):

• heap/Subspace.cpp:

(JSC::Subspace::initialize):

• heap/Subspace.h:

Source/WTF:

• wtf/FastBitVector.h:

(WTF::fastBitVectorArrayLength):
(WTF::FastBitVectorImpl::unsafeWords):
(WTF::FastBitVectorImpl::unsafeWords const):
(WTF::FastBitReference::FastBitReference):
(WTF::FastBitReference::operator bool const):
(WTF::FastBitReference::operator=):
(WTF::FastBitVector::at):
(WTF::FastBitVector::operator[]):
(WTF::FastBitVector::BitReference::BitReference): Deleted.
(WTF::FastBitVector::BitReference::operator bool const): Deleted.
(WTF::FastBitVector::BitReference::operator=): Deleted.

File:

• trunk/Source/JavaScriptCore/heap/IsoSubspacePerVM.cpp (modified) (1 diff)

trunk/Source/JavaScriptCore/heap/IsoSubspacePerVM.cpp

@@ -42 +42 @@
     {
         auto locker = holdLock(m_perVM.m_lock);
-        m_perVM.m_subspacePerVM.remove(&space().heap()->vm());
+        m_perVM.m_subspacePerVM.remove(&space().heap().vm());
     }