[heap] Remove PromotionMode used by Scavenger

[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org

Committed: https://crrev.com/f88fe51a00bb66d6e47e1e12193cb5125dfa63b1
Cr-Commit-Position: refs/heads/master@{#40026}

[Michael Lippautz, 2016-10-05 11:11:29]

Description was changed from

==========
[heap] Remove promotionmode from scavenging

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

BUG=
==========

to

==========
[heap] Remove promotionmode from scavenging

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=
==========

[Michael Lippautz, 2016-10-05 11:12:00]

Description was changed from

==========
[heap] Remove promotionmode from scavenging

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=
==========

[Michael Lippautz, 2016-10-05 11:12:15]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

[Michael Lippautz, 2016-10-05 11:17:41]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking.

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

[Michael Lippautz, 2016-10-05 11:50:46]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

[Michael Lippautz, 2016-10-05 11:50:46]

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

[Michael Lippautz, 2016-10-05 11:50:55]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org
==========

[Michael Lippautz, 2016-10-05 11:50:55]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org
==========

[Michael Lippautz, 2016-10-05 11:51:12]

as discussed offline, let us remove this mode

[Michael Lippautz, 2016-10-05 11:51:26]

The CQ bit was checked by mlippautz@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-10-05 11:51:32]

Dry run: 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, 2016-10-05 12:22:03]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-10-05 12:22:05]

Dry run: This issue passed the CQ dry run.

[Hannes Payer (out of office), 2016-10-06 10:09:48]

lgtm

[Michael Lippautz, 2016-10-06 10:11:27]

The CQ bit was checked by mlippautz@chromium.org

[commit-bot: I haz the power, 2016-10-06 10:11:31]

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, 2016-10-06 10:14:13]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org
==========

[commit-bot: I haz the power, 2016-10-06 10:14:14]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-06 10:14:28]

Description was changed from

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org
==========

to

==========
[heap] Remove PromotionMode used by Scavenger

The scavenger should never consider mark bits for promotion/copy as this creates
weird livetimes at the start of incremental marking. E.g. consider an object
marked black by the marker at the start of incremental marking. A scavenge would
promote it to the old generation although it could --and for short-living
objects actually does-- become unreachable during marking

Also, keeping this invariant significantly simplifies young generation mark
compacting as we can compare against the scavenging decision without keeping
different sets of markbits.

BUG=chromium:651354
R=hpayer@chromium.org

Committed: https://crrev.com/f88fe51a00bb66d6e47e1e12193cb5125dfa63b1
Cr-Commit-Position: refs/heads/master@{#40026}
==========

[commit-bot: I haz the power, 2016-10-06 10:14:29]

Patchset 2 (id:??) landed as
https://crrev.com/f88fe51a00bb66d6e47e1e12193cb5125dfa63b1
Cr-Commit-Position: refs/heads/master@{#40026}