Changeset 128141 in webkit for trunk/Source/JavaScriptCore/runtime

Timestamp:

Sep 10, 2012, 8:02:46 PM (13 years ago)

Author:

[email protected]

Message:

Added large allocation support to MarkedSpace
​https://bugs.webkit.org/show_bug.cgi?id=96214

Originally reviewed by Oliver Hunt, then I added a design revision by
suggested by Phil Pizlo.

I expanded the imprecise size classes to cover up to 32KB, then added
an mmap-based allocator for everything bigger. There's a lot of tuning
we could do in these size classes, but currently they're almost
completely unused, so I haven't done any tuning.

Subtle point: the large allocator is a degenerate case of our free list
logic. Its list only ever contains zero or one items.

• heap/Heap.h:

(JSC::Heap::allocateStructure): Pipe in size information.

• heap/MarkedAllocator.cpp:

(JSC::MarkedAllocator::tryAllocateHelper): Handle the case where we
find a free item in the sweep list but the item isn't big enough. This
can happen in the large allocator because it mixes sizes.

(JSC::MarkedAllocator::tryAllocate):
(JSC::MarkedAllocator::allocateSlowCase): More piping.

(JSC::MarkedAllocator::allocateBlock): Handle the oversize case.

(JSC::MarkedAllocator::addBlock): I moved the call to didAddBlock here
because it made more sense.

• heap/MarkedAllocator.h:

(MarkedAllocator):
(JSC::MarkedAllocator::allocate):

• heap/MarkedSpace.cpp:

(JSC::MarkedSpace::MarkedSpace):
(JSC::MarkedSpace::resetAllocators):
(JSC::MarkedSpace::canonicalizeCellLivenessData):
(JSC::MarkedSpace::isPagedOut):
(JSC::MarkedSpace::freeBlock):

• heap/MarkedSpace.h:

(MarkedSpace):
(JSC::MarkedSpace::allocatorFor):
(JSC::MarkedSpace::destructorAllocatorFor):
(JSC::MarkedSpace::allocateWithoutDestructor):
(JSC::MarkedSpace::allocateWithDestructor):
(JSC::MarkedSpace::allocateStructure):
(JSC::MarkedSpace::forEachBlock):

• runtime/Structure.h:

(JSC::Structure): More piping.

File:

• trunk/Source/JavaScriptCore/runtime/Structure.h (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/Structure.h

@@ -461 +461 @@
         heap.globalData()->setInitializingObjectClass(&Structure::s_info);
 #endif
-        JSCell* result = static_cast<JSCell*>(heap.allocateStructure());
+        JSCell* result = static_cast<JSCell*>(heap.allocateStructure(sizeof(Structure)));
         result->clearStructure();
         return result;