[heap] Take page lock when scavenging old to new references in Scavenger.

[heap] Take page lock when scavenging old to new references in Scavenger.

BUG=v8:5807
Review-Url: https://codereview.chromium.org/2781363002
Cr-Commit-Position: refs/heads/master@{#44268}
Committed: https://chromium.googlesource.com/v8/v8/+/4024e6a1bb0b803a5cd16fcd11f39cc305b943c6

[Hannes Payer (out of office), 2017-03-30 11:40:36]

hpayer@chromium.org changed reviewers:
+ ulan@chromium.org

[ulan, 2017-03-30 12:04:18]

lgtm with comment

https://codereview.chromium.org/2781363002/diff/1/src/heap/heap.cc
File src/heap/heap.cc (right):

https://codereview.chromium.org/2781363002/diff/1/src/heap/heap.cc#newcode1726
src/heap/heap.cc:1726: RememberedSet<OLD_TO_NEW>::Iterate(this, true,
[this](Address addr) {
Let's use enum here as we usually do.

[Hannes Payer (out of office), 2017-03-30 12:48:55]

The CQ bit was checked by hpayer@chromium.org

[Hannes Payer (out of office), 2017-03-30 12:48:55]

The patchset sent to the CQ was uploaded after l-g-t-m from ulan@chromium.org
Link to the patchset: https://codereview.chromium.org/2781363002/#ps20001
(title: "enum")

[commit-bot: I haz the power, 2017-03-30 12:49:09]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-30 13:14:02]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1490878135141540,
"parent_rev": "1200cc2c6d715466ee762a05ae26fe4a4f82eb36", "commit_rev":
"4024e6a1bb0b803a5cd16fcd11f39cc305b943c6"}

[commit-bot: I haz the power, 2017-03-30 13:14:08]

Description was changed from

==========
[heap] Take page lock when scavenging old to new references in Scavenger.

BUG=v8:5807
==========

to

==========
[heap] Take page lock when scavenging old to new references in Scavenger.

BUG=v8:5807

Review-Url: https://codereview.chromium.org/2781363002
Cr-Commit-Position: refs/heads/master@{#44268}
Committed:
https://chromium.googlesource.com/v8/v8/+/4024e6a1bb0b803a5cd16fcd11f39cc305b...
==========

[commit-bot: I haz the power, 2017-03-30 13:14:10]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/4024e6a1bb0b803a5cd16fcd11f39cc305b...

[Hannes Payer (out of office), 2017-03-31 10:45:38]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/2786313003/ by hpayer@chromium.org.

The reason for reverting is: This results in a deadlock when the scavenger
decides to perform sweeping and re-grabs the same mutex..