Print out how many AllocationMementos were found on a scavenge of new space

Print out how many AllocationMementos were found on a scavenge of new
space. This is useful because the unrooted mementos affect heap
decisions like pretenuring mode, and helps to gauge the effectiveness
of allocation-site feedback.

R=hpayer@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=17027

[mvstanton, 2013-09-30 13:56:05]

Hi Hannes, PTAL, thx!

[Hannes Payer (out of office), 2013-09-30 19:02:56]

LGTM with two nits.

https://codereview.chromium.org/25273002/diff/1/src/heap.h
File src/heap.h (right):

https://codereview.chromium.org/25273002/diff/1/src/heap.h#newcode1890
src/heap.h:1890: int mementos_found_on_scavenge_;
allocation_mementos_found_on_scavenge_

https://codereview.chromium.org/25273002/diff/1/src/objects.cc
File src/objects.cc (left):

https://codereview.chromium.org/25273002/diff/1/src/objects.cc#oldcode9060
src/objects.cc:9060: ASSERT(object->GetHeap()->InToSpace(object));
Instead of deleting this assert, we could assert that the object is in new
space.

[Hannes Payer (out of office), 2013-09-30 19:04:43]

Please fix the title, it got trimmed.

[mvstanton, 2013-09-30 20:45:30]

thanks Hannes!
--Michael

https://codereview.chromium.org/25273002/diff/1/src/heap.h
File src/heap.h (right):

https://codereview.chromium.org/25273002/diff/1/src/heap.h#newcode1890
src/heap.h:1890: int mementos_found_on_scavenge_;
On 2013/09/30 19:02:56, Hannes Payer wrote:
> allocation_mementos_found_on_scavenge_

Done.

https://codereview.chromium.org/25273002/diff/1/src/objects.cc
File src/objects.cc (left):

https://codereview.chromium.org/25273002/diff/1/src/objects.cc#oldcode9060
src/objects.cc:9060: ASSERT(object->GetHeap()->InToSpace(object));
On 2013/09/30 19:02:56, Hannes Payer wrote:
> Instead of deleting this assert, we could assert that the object is in new
> space.

Actually that is already done, in the if() statement above. Thx though, good
instinct!!

[mvstanton, 2013-10-01 08:14:54]

Committed patchset #2 manually as r17027 (presubmit successful).