[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

Currently the VisitObject function iterates the object and then colors
it black. This does not work well with concurrent marking. The function
should instead first try to mark the object black and iterate its body
only if the color transition succeeds.

BUG=chromium:694255
Review-Url: https://codereview.chromium.org/2853323003
Cr-Commit-Position: refs/heads/master@{#45095}
Committed: https://chromium.googlesource.com/v8/v8/+/00d1e2cf766f982f7e2b4841de82c2458d09c319

[ulan, 2017-05-02 19:34:55]

Description was changed from

==========
[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

Currently the VisitObject function iterates the object and then colors
it black. This does not work well with concurrent marking. The function
should instead first try to mark the object black and iterate its body
only if the color transition suceeeds.

BUG=chromium:694255
==========

to

==========
[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

Currently the VisitObject function iterates the object and then colors
it black. This does not work well with concurrent marking. The function
should instead first try to mark the object black and iterate its body
only if the color transition succeeds.

BUG=chromium:694255
==========

[ulan, 2017-05-02 19:36:07]

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

[ulan, 2017-05-02 19:36:08]

ptal

[Michael Lippautz, 2017-05-03 07:51:49]

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
src/heap/incremental-marking.cc:814: if
(ObjectMarking::GreyToBlack<kAtomicity>(obj, marking_state(obj))) {
GreyToWhite?

Otherwise WhiteToGreyAndPush will be a noop?

[ulan, 2017-05-03 09:03:54]

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
src/heap/incremental-marking.cc:814: if
(ObjectMarking::GreyToBlack<kAtomicity>(obj, marking_state(obj))) {
On 2017/05/03 07:51:49, Michael Lippautz wrote:
> GreyToWhite?
> Otherwise WhiteToGreyAndPush will be a noop?
WhiteToGreyAndPush applies to the map.
The object is grey or black at this point. If we succeed in transitioning it to
black then we iterate its map and body.

[Hannes Payer (out of office), 2017-05-03 10:03:14]

lgtm

[Michael Lippautz, 2017-05-03 10:05:39]

lgtm

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
File src/heap/incremental-marking.cc (right):

https://codereview.chromium.org/2853323003/diff/1/src/heap/incremental-markin...
src/heap/incremental-marking.cc:814: if
(ObjectMarking::GreyToBlack<kAtomicity>(obj, marking_state(obj))) {
On 2017/05/03 09:03:54, ulan wrote:
> On 2017/05/03 07:51:49, Michael Lippautz wrote:
> > GreyToWhite?
> > Otherwise WhiteToGreyAndPush will be a noop?
> WhiteToGreyAndPush applies to the map.
> The object is grey or black at this point. If we succeed in transitioning it
to
> black then we iterate its map and body.

Thanks :)

[ulan, 2017-05-04 12:42:00]

The CQ bit was checked by ulan@chromium.org

[ulan, 2017-05-04 12:42:01]

The patchset sent to the CQ was uploaded after l-g-t-m from hpayer@chromium.org,
mlippautz@chromium.org
Link to the patchset: https://codereview.chromium.org/2853323003/#ps40001
(title: "rebase")

[commit-bot: I haz the power, 2017-05-04 12:42:04]

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, 2017-05-04 13:11:46]

CQ is committing da patch.

Bot data: {"patchset_id": 40001, "attempt_start_ts": 1493901720970280,
"parent_rev": "2ec36b675e16693891986c10665b0e126defa10e", "commit_rev":
"00d1e2cf766f982f7e2b4841de82c2458d09c319"}

[commit-bot: I haz the power, 2017-05-04 13:11:52]

Description was changed from

==========
[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

Currently the VisitObject function iterates the object and then colors
it black. This does not work well with concurrent marking. The function
should instead first try to mark the object black and iterate its body
only if the color transition succeeds.

BUG=chromium:694255
==========

to

==========
[heap] Prepare IncrementalMarking::VisitObject for concurrent marking.

Currently the VisitObject function iterates the object and then colors
it black. This does not work well with concurrent marking. The function
should instead first try to mark the object black and iterate its body
only if the color transition succeeds.

BUG=chromium:694255

Review-Url: https://codereview.chromium.org/2853323003
Cr-Commit-Position: refs/heads/master@{#45095}
Committed:
https://chromium.googlesource.com/v8/v8/+/00d1e2cf766f982f7e2b4841de82c2458d0...
==========

[commit-bot: I haz the power, 2017-05-04 13:11:53]

Committed patchset #3 (id:40001) as
https://chromium.googlesource.com/v8/v8/+/00d1e2cf766f982f7e2b4841de82c2458d0...