Reviewers: Vyacheslav Egorov,
Description:
Avoid extra GCs when deserializing during incremental marking.
Please review this at http://codereview.chromium.org/8276030/
SVN Base: http://v8.googlecode.com/svn/branches/bleeding_edge/
Affected files:
M src/spaces.cc
Index: src/spaces.cc
===================================================================
--- src/spaces.cc (revision 9609)
+++ src/spaces.cc (working copy)
@@ -1909,11 +1909,24 @@
bool NewSpace::ReserveSpace(int bytes) {
// We can't reliably unpack a partial snapshot that needs more new space
- // space than the minimum NewSpace size.
+ // space than the minimum NewSpace size. The limit can be set lower than
+ // the end of new space either because there is more space on the next
page
+ // or because we have lowered the limit in order to get periodic
incremental
+ // marking. The most reliable way to ensure that there is linear space
is
+ // to do the allocation, then rewind the limit.
ASSERT(bytes <= InitialCapacity());
- Address limit = allocation_info_.limit;
+ MaybeObject* maybe = AllocateRawInternal(bytes);
+ Object* object = NULL;
+ if (!maybe->ToObject(&object)) return false;
+ HeapObject* allocation = HeapObject::cast(object);
Address top = allocation_info_.top;
- return limit - top >= bytes;
+ if (top - bytes == allocation->address()) {
+ allocation_info_.top = allocation->address();
+ return true;
+ }
+ // There may be a borderline case here where the allocation succeeded,
but
+ // the limit and top have moved on to a new page. In that case we try
again.
+ return ReserveSpace(bytes);
}
--
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