Changeset 134080 in webkit for trunk/Source/JavaScriptCore/heap/MarkStack.h

Timestamp:

Nov 9, 2012, 9:58:19 AM (13 years ago)

Author:

[email protected]

Message:

MarkStackArray should use the BlockAllocator instead of the MarkStackSegmentAllocator
​https://bugs.webkit.org/show_bug.cgi?id=101642

Reviewed by Filip Pizlo.

MarkStackSegmentAllocator is like a miniature version of the BlockAllocator. Now that the BlockAllocator has support
for a variety of block sizes, we should get rid of the MarkStackSegmentAllocator in favor of the BlockAllocator.

• heap/BlockAllocator.h: Add new specializations of regionSetFor for the new MarkStackSegments.

(JSC):
(JSC::MarkStackSegment):

• heap/GCThreadSharedData.cpp:

(JSC::GCThreadSharedData::GCThreadSharedData):
(JSC::GCThreadSharedData::reset):

• heap/GCThreadSharedData.h:

(GCThreadSharedData):

• heap/MarkStack.cpp:

(JSC::MarkStackArray::MarkStackArray): We now have a doubly linked list of MarkStackSegments, so we need to refactor
all the places that used the old custom tail/previous logic.
(JSC::MarkStackArray::~MarkStackArray):
(JSC::MarkStackArray::expand):
(JSC::MarkStackArray::refill):
(JSC::MarkStackArray::donateSomeCellsTo): Refactor to use the new linked list.
(JSC::MarkStackArray::stealSomeCellsFrom): Ditto.

• heap/MarkStack.h:

(JSC):
(MarkStackSegment):
(JSC::MarkStackSegment::MarkStackSegment):
(JSC::MarkStackSegment::sizeFromCapacity):
(MarkStackArray):

• heap/MarkStackInlines.h:

(JSC::MarkStackSegment::create):
(JSC):
(JSC::MarkStackArray::postIncTop):
(JSC::MarkStackArray::preDecTop):
(JSC::MarkStackArray::setTopForFullSegment):
(JSC::MarkStackArray::setTopForEmptySegment):
(JSC::MarkStackArray::top):
(JSC::MarkStackArray::validatePrevious):
(JSC::MarkStackArray::append):
(JSC::MarkStackArray::removeLast):
(JSC::MarkStackArray::isEmpty):
(JSC::MarkStackArray::size):

• heap/SlotVisitor.cpp:

(JSC::SlotVisitor::SlotVisitor):

File:

• trunk/Source/JavaScriptCore/heap/MarkStack.h (modified) (3 diffs)

trunk/Source/JavaScriptCore/heap/MarkStack.h

@@ -51 +51 @@
 #endif
 
+#include "HeapBlock.h"
 #include <wtf/StdLibExtras.h>
-#include <wtf/TCSpinLock.h>
 
 namespace JSC {
 
+class BlockAllocator;
+class DeadBlock;
 class JSCell;
 
-struct MarkStackSegment {
-    MarkStackSegment* m_previous;
+class MarkStackSegment : public HeapBlock<MarkStackSegment> {
+public:
+    MarkStackSegment(Region* region)
+        : HeapBlock<MarkStackSegment>(region)
 #if !ASSERT_DISABLED
-    size_t m_top;
+        , m_top(0)
 #endif
-        
+    {
+    }
+
+    static MarkStackSegment* create(DeadBlock*);
+
     const JSCell** data()
     {
@@ -78 +86 @@
         return sizeof(MarkStackSegment) + capacity * sizeof(const JSCell*);
     }
-};
 
-class MarkStackSegmentAllocator {
-public:
-    MarkStackSegmentAllocator();
-    ~MarkStackSegmentAllocator();
-    
-    MarkStackSegment* allocate();
-    void release(MarkStackSegment*);
-    
-    void shrinkReserve();
-    
-private:
-    SpinLock m_lock;
-    MarkStackSegment* m_nextFreeSegment;
+    static const size_t blockSize = 4 * KB;
+
+#if !ASSERT_DISABLED
+    size_t m_top;
+#endif
 };
 
 class MarkStackArray {
 public:
-    MarkStackArray(MarkStackSegmentAllocator&);
+    MarkStackArray(BlockAllocator&);
     ~MarkStackArray();
 
@@ -123 +122 @@
     void validatePrevious();
 
-    MarkStackSegment* m_topSegment;
-    MarkStackSegmentAllocator& m_allocator;
+    DoublyLinkedList<MarkStackSegment> m_segments;
+    BlockAllocator& m_blockAllocator;
 
     size_t m_segmentCapacity;
     size_t m_top;
-    size_t m_numberOfPreviousSegments;
+    size_t m_numberOfSegments;
    
 };