Introduce lazy sweeping.

Introduce lazy sweeping.

Committed: http://code.google.com/p/v8/source/detail?r=7836

[Erik Corry, 2011-05-09 21:20:11]

LGTM

http://codereview.chromium.org/6970004/diff/1/src/incremental-marking.cc
File src/incremental-marking.cc (right):

http://codereview.chromium.org/6970004/diff/1/src/incremental-marking.cc#newc...
src/incremental-marking.cc:154: ClearMarkbits(heap_->code_space());
Who clears the mark bits in the large object space?

http://codereview.chromium.org/6970004/diff/1/src/mark-compact.cc
File src/mark-compact.cc (right):

http://codereview.chromium.org/6970004/diff/1/src/mark-compact.cc#newcode2540
src/mark-compact.cc:2540: return;
I think we will want to tune this heuristic.  If we are not finding any garbage
to put on the free list then we shouldn't sweep the whole old space before
giving up and expanding the old space.  That will cause too long a pause for no
gain.

http://codereview.chromium.org/6970004/diff/1/src/spaces.h
File src/spaces.h (right):

http://codereview.chromium.org/6970004/diff/1/src/spaces.h#newcode1021
src/spaces.h:1021: 
Extra blank line here.

[antonm, 2011-05-10 13:09:38]

DBC

http://codereview.chromium.org/6970004/diff/1/src/incremental-marking.cc
File src/incremental-marking.cc (right):

http://codereview.chromium.org/6970004/diff/1/src/incremental-marking.cc#newc...
src/incremental-marking.cc:242: PrintF("[IncrementalMarking] Start
sweeping.\n");
if (FLAG_trace_incremental_marking)?