[heap] Make survival counters concurrent (atomic)

[heap] Make survival counters concurrent (atomic)

Those counters will be incremented concurrently during parallel evacuation of
newspace. This change makes sure we do the updates atomically.

Note that actual reasoning about them happens sequentially on the main thread.

BUG=chromium:524425
LOG=N
R=ulan@chromium.org

Committed: https://crrev.com/7cf64f4017fdfc8e39afb5ab1940a37fe2e02ca3
Cr-Commit-Position: refs/heads/master@{#33326}

[Michael Lippautz, 2016-01-15 11:56:53]

PTAl, this is the other small spin-off from the parallel evacuation prototype.

[Michael Lippautz, 2016-01-15 11:57:03]

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

[commit-bot: I haz the power, 2016-01-15 11:57:10]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1585843010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1585843010/1

[ulan, 2016-01-15 12:01:29]

lgtm

[commit-bot: I haz the power, 2016-01-15 12:19:23]

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

[commit-bot: I haz the power, 2016-01-15 12:19:24]

Dry run: This issue passed the CQ dry run.

[Michael Lippautz, 2016-01-15 12:19:55]

The CQ bit was checked by mlippautz@chromium.org

[commit-bot: I haz the power, 2016-01-15 12:20:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1585843010/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1585843010/1

[commit-bot: I haz the power, 2016-01-15 12:23:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-01-15 12:23:37]

Description was changed from

==========
[heap] Make survival counters concurrent (atomic)

Those counters will be incremented concurrently during parallel evacuation of
newspace. This change makes sure we do the updates atomically.

Note that actual reasoning about them happens sequentially on the main thread.

BUG=chromium:524425
LOG=N
R=ulan@chromium.org
==========

to

==========
[heap] Make survival counters concurrent (atomic)

Those counters will be incremented concurrently during parallel evacuation of
newspace. This change makes sure we do the updates atomically.

Note that actual reasoning about them happens sequentially on the main thread.

BUG=chromium:524425
LOG=N
R=ulan@chromium.org

Committed: https://crrev.com/7cf64f4017fdfc8e39afb5ab1940a37fe2e02ca3
Cr-Commit-Position: refs/heads/master@{#33326}
==========

[commit-bot: I haz the power, 2016-01-15 12:23:37]

Patchset 1 (id:??) landed as
https://crrev.com/7cf64f4017fdfc8e39afb5ab1940a37fe2e02ca3
Cr-Commit-Position: refs/heads/master@{#33326}