Use PhantomReference for CleanupReference

android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.

Committed: https://crrev.com/9b1b3599500eca2b8d664714edf6b6771a789123
Cr-Commit-Position: refs/heads/master@{#381173}

[boliu, 2016-03-15 03:10:50]

Description was changed from

==========
Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.
==========

to

==========
android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.
==========

[boliu, 2016-03-15 03:11:09]

boliu@chromium.org changed reviewers:
+ dtrainor@chromium.org

[boliu, 2016-03-15 03:11:10]

ptal

[michaelbai, 2016-03-15 03:19:36]

On 2016/03/15 03:11:10, boliu wrote:
> ptal


The information I got is PhantomRefs is faster on ART, what's about old
platform? Should you apply different implementation for different platform?

[boliu, 2016-03-15 03:22:04]

On 2016/03/15 03:19:36, michaelbai wrote:
> On 2016/03/15 03:11:10, boliu wrote:
> > ptal
> 
> 
> The information I got is PhantomRefs is faster on ART, what's about old
> platform? Should you apply different implementation for different platform?

Improvement is *even more* on dalvik than on art.

What other implementation are you referring though? Inherently PhantomReference
makes less promise than WeakReference, so in theory it should only be faster
than WeakReference on any jvm.

[David Trainor- moved to gerrit, 2016-03-15 03:22:45]

lgtm thanks for the thread!

[boliu, 2016-03-15 03:48:15]

The CQ bit was checked by boliu@chromium.org

[commit-bot: I haz the power, 2016-03-15 03:48:22]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1802233002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1802233002/1

[commit-bot: I haz the power, 2016-03-15 04:21:02]

Description was changed from

==========
android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.
==========

to

==========
android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.
==========

[commit-bot: I haz the power, 2016-03-15 04:21:03]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-15 04:22:03]

Description was changed from

==========
android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.
==========

to

==========
android: Use PhantomReference for CleanupReference

PhantomReference is less of a burden on dalvik/art gc systems.

Committed: https://crrev.com/9b1b3599500eca2b8d664714edf6b6771a789123
Cr-Commit-Position: refs/heads/master@{#381173}
==========

[commit-bot: I haz the power, 2016-03-15 04:22:04]

Patchset 1 (id:??) landed as
https://crrev.com/9b1b3599500eca2b8d664714edf6b6771a789123
Cr-Commit-Position: refs/heads/master@{#381173}

[boliu, 2016-03-17 19:15:03]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1815443002/ by boliu@chromium.org.

The reason for reverting is: Found out that PhantomReference can survive (ie not
get enqueued) a GC pass. Tested on Android M.

This would cause unacceptable memory regressions for apps that relies on gc to
clean up webview..