JDK-8271870 : G1: Add objArray splitting when scanning object with evacuation failure
Type:Enhancement
Component:hotspot
Sub-Component:gc
Affected Version:18
Priority:P4
Status:Resolved
Resolution:Fixed
Submitted:2021-08-04
Updated:2025-04-14
Resolved:2025-04-03
The Version table provides details related to the release that this issue/RFE will be addressed.
Unresolved : Release in which this issue/RFE will be addressed. Resolved: Release in which this issue/RFE has been resolved. Fixed : Release in which this issue/RFE has been fixed. The release containing this fix may be available for download as an Early Access Release or a General Availability Release.
A pull request was submitted for review.
Branch: master
URL: https://git.openjdk.org/jdk/pull/24222
Date: 2025-03-25 10:35:58 +0000
01-04-2025
[~mli]: I took this over after not much activity for some time.
https://github.com/tschatzl/jdk/tree/submit/8271870-evac-fail-split-array contains a prototype.
25-03-2025
With JDK-8337709 this optimzation should now be doable.
13-09-2024
Objects in young gen can be half a region size. Half a region size is 16M (well, 256M soon), ie. up to ~4M (64M) pointers; currently these pointers are scanned by a single thread, without the task stepper - i.e. basically copying that array onto the task queue.
That seems inefficient.
Note that this is (probably) not easy to do, so let's not make this top priority (and optional) for a first cut.
09-11-2021
Not quite sure whether we need to split an array which failed evacuation.