Imported WebKit commit eb5c1b8fe4d4b1b90b5137433fc58a91da0e6878 (http://svn.webkit.org/repository/webkit/trunk@118516)

1 files changed, 58 insertions, 53 deletions

diff --git a/Source/JavaScriptCore/heap/Heap.cpp b/Source/JavaScriptCore/heap/Heap.cpp
index 2254b5b01..9b68fb10a 100644
--- a/Source/JavaScriptCore/heap/Heap.cpp
+++ b/Source/JavaScriptCore/heap/Heap.cpp
@@ -35,9 +35,9 @@
 #include "Tracing.h"
 #include "WeakSetInlines.h"
 #include <algorithm>
+#include <wtf/RAMSize.h>
 #include <wtf/CurrentTime.h>
 
-
 using namespace std;
 using namespace JSC;
 
@@ -45,14 +45,8 @@ namespace JSC {
 
 namespace { 
 
-#if CPU(X86) || CPU(X86_64)
-static const size_t largeHeapSize = 16 * 1024 * 1024;
-#elif PLATFORM(IOS)
-static const size_t largeHeapSize = 8 * 1024 * 1024;
-#else
-static const size_t largeHeapSize = 512 * 1024;
-#endif
-static const size_t smallHeapSize = 512 * 1024;
+static const size_t largeHeapSize = 32 * MB; // About 1.5X the average webpage.
+static const size_t smallHeapSize = 1 * MB; // Matches the FastMalloc per-thread cache.
 
 #if ENABLE(GC_LOGGING)
 #if COMPILER(CLANG)
@@ -148,14 +142,23 @@ struct GCCounter {
 #define GCCOUNTER(name, value) do { } while (false)
 #endif
 
-static size_t heapSizeForHint(HeapSize heapSize)
+static inline size_t minHeapSize(HeapType heapType, size_t ramSize)
 {
-    if (heapSize == LargeHeap)
-        return largeHeapSize;
-    ASSERT(heapSize == SmallHeap);
+    if (heapType == LargeHeap)
+        return min(largeHeapSize, ramSize / 4);
     return smallHeapSize;
 }
 
+static inline size_t proportionalHeapSize(size_t heapSize, size_t ramSize)
+{
+    // Try to stay under 1/2 RAM size to leave room for the DOM, rendering, networking, etc.
+    if (heapSize < ramSize / 4)
+        return 2 * heapSize;
+    if (heapSize < ramSize / 2)
+        return 1.5 * heapSize;
+    return 1.25 * heapSize;
+}
+
 static inline bool isValidSharedInstanceThreadState()
 {
     if (!JSLock::lockCount())
@@ -230,9 +233,10 @@ inline PassOwnPtr<TypeCountSet> RecordType::returnValue()
 
 } // anonymous namespace
 
-Heap::Heap(JSGlobalData* globalData, HeapSize heapSize)
-    : m_heapSize(heapSize)
-    , m_minBytesPerCycle(heapSizeForHint(heapSize))
+Heap::Heap(JSGlobalData* globalData, HeapType heapType)
+    : m_heapType(heapType)
+    , m_ramSize(ramSize())
+    , m_minBytesPerCycle(minHeapSize(m_heapType, m_ramSize))
     , m_sizeAfterLastCollect(0)
     , m_bytesAllocatedLimit(m_minBytesPerCycle)
     , m_bytesAllocated(0)
@@ -240,12 +244,10 @@ Heap::Heap(JSGlobalData* globalData, HeapSize heapSize)
     , m_operationInProgress(NoOperation)
     , m_objectSpace(this)
     , m_storageSpace(this)
-    , m_markListSet(0)
     , m_activityCallback(DefaultGCActivityCallback::create(this))
     , m_machineThreads(this)
     , m_sharedData(globalData)
     , m_slotVisitor(m_sharedData)
-    , m_weakSet(this)
     , m_handleSet(globalData)
     , m_isSafeToCollect(false)
     , m_globalData(globalData)
@@ -257,13 +259,6 @@ Heap::Heap(JSGlobalData* globalData, HeapSize heapSize)
 
 Heap::~Heap()
 {
-    delete m_markListSet;
-
-    m_objectSpace.shrink();
-    m_storageSpace.freeAllBlocks();
-
-    ASSERT(!size());
-    ASSERT(!capacity());
 }
 
 bool Heap::isPagedOut(double deadline)
@@ -282,11 +277,7 @@ void Heap::lastChanceToFinalize()
     if (size_t size = m_protectedValues.size())
         WTFLogAlways("ERROR: JavaScriptCore heap deallocated while %ld values were still protected", static_cast<unsigned long>(size));
 
-    m_weakSet.finalizeAll();
-    m_objectSpace.canonicalizeCellLivenessData();
-    m_objectSpace.clearMarks();
-    m_objectSpace.sweep();
-    m_globalData->smallStrings.finalizeSmallStrings();
+    m_objectSpace.lastChanceToFinalize();
 
 #if ENABLE(SIMPLE_HEAP_PROFILING)
     m_slotVisitor.m_visitedTypeCounts.dump(WTF::dataFile(), "Visited Type Counts");
@@ -451,6 +442,15 @@ void Heap::markRoots(bool fullGC)
         GCPHASE(GatherRegisterFileRoots);
         registerFile().gatherConservativeRoots(registerFileRoots, m_dfgCodeBlocks);
     }
+
+#if ENABLE(DFG_JIT)
+    ConservativeRoots scratchBufferRoots(&m_objectSpace.blocks(), &m_storageSpace);
+    {
+        GCPHASE(GatherScratchBufferRoots);
+        m_globalData->gatherConservativeRoots(scratchBufferRoots);
+    }
+#endif
+
 #if ENABLE(GGC)
     MarkedBlock::DirtyCellVector dirtyCells;
     if (!fullGC) {
@@ -497,6 +497,13 @@ void Heap::markRoots(bool fullGC)
             visitor.append(registerFileRoots);
             visitor.donateAndDrain();
         }
+#if ENABLE(DFG_JIT)
+        {
+            GCPHASE(VisitScratchBufferRoots);
+            visitor.append(scratchBufferRoots);
+            visitor.donateAndDrain();
+        }
+#endif
         {
             GCPHASE(VisitProtectedObjects);
             markProtectedObjects(heapRootVisitor);
@@ -552,7 +559,7 @@ void Heap::markRoots(bool fullGC)
     {
         GCPHASE(VisitingLiveWeakHandles);
         while (true) {
-            m_weakSet.visitLiveWeakImpls(heapRootVisitor);
+            m_objectSpace.visitWeakSets(heapRootVisitor);
             harvestWeakReferences();
             if (visitor.isEmpty())
                 break;
@@ -566,11 +573,6 @@ void Heap::markRoots(bool fullGC)
         }
     }
 
-    {
-        GCPHASE(VisitingDeadWeakHandles);
-        m_weakSet.visitDeadWeakImpls(heapRootVisitor);
-    }
-
     GCCOUNTER(VisitedValueCount, visitor.visitCount());
 
     visitor.doneCopying();
@@ -674,25 +676,24 @@ void Heap::collect(SweepToggle sweepToggle)
     markRoots(fullGC);
     
     {
+        GCPHASE(ReapingWeakHandles);
+        m_objectSpace.reapWeakSets();
+    }
+
+    {
         GCPHASE(FinalizeUnconditionalFinalizers);
         finalizeUnconditionalFinalizers();
     }
-        
+
     {
         GCPHASE(FinalizeWeakHandles);
-        m_weakSet.sweep();
+        m_objectSpace.sweepWeakSets();
         m_globalData->smallStrings.finalizeSmallStrings();
     }
     
     JAVASCRIPTCORE_GC_MARKED();
 
     {
-        GCPHASE(ResetAllocators);
-        m_objectSpace.resetAllocators();
-        m_weakSet.resetAllocator();
-    }
-    
-    {
         GCPHASE(DeleteCodeBlocks);
         m_dfgCodeBlocks.deleteUnmarkedJettisonedCodeBlocks();
     }
@@ -702,19 +703,23 @@ void Heap::collect(SweepToggle sweepToggle)
         GCPHASE(Sweeping);
         m_objectSpace.sweep();
         m_objectSpace.shrink();
-        m_weakSet.shrink();
         m_bytesAbandoned = 0;
     }
 
-    // To avoid pathological GC churn in large heaps, we set the new allocation 
-    // limit to be the current size of the heap. This heuristic 
-    // is a bit arbitrary. Using the current size of the heap after this 
-    // collection gives us a 2X multiplier, which is a 1:1 (heap size :
-    // new bytes allocated) proportion, and seems to work well in benchmarks.
-    size_t newSize = size();
+    {
+        GCPHASE(ResetAllocators);
+        m_objectSpace.resetAllocators();
+    }
+    
+    size_t currentHeapSize = size();
     if (fullGC) {
-        m_sizeAfterLastCollect = newSize;
-        m_bytesAllocatedLimit = max(newSize, m_minBytesPerCycle);
+        m_sizeAfterLastCollect = currentHeapSize;
+
+        // To avoid pathological GC churn in very small and very large heaps, we set
+        // the new allocation limit based on the current size of the heap, with a
+        // fixed minimum.
+        size_t maxHeapSize = max(minHeapSize(m_heapType, m_ramSize), proportionalHeapSize(currentHeapSize, m_ramSize));
+        m_bytesAllocatedLimit = maxHeapSize - currentHeapSize;
     }
     m_bytesAllocated = 0;
     double lastGCEndTime = WTF::currentTime();