JDK-8140326 : G1: Consider putting regions where evacuation failed into next collection set
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 9
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2015-10-22
  • Updated: 2023-09-05
  • Resolved: 2023-08-08
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JDK 22
22 b10Fixed
Related Reports
Blocks :  
JDK-8306920 - G1: Calculate garbage bytes for evacuation failed regions from marked live bytes
Relates :  
JDK-8314157 - G1: "yielded" is not initialized on some paths after JDK-8140326
Relates :  
JDK-8315501 - G1: Do not require marking region evacuation in Prepare Mixed GC
Relates :  
JDK-8300770 - G1: Allow optional code root memregions
Relates :  
JDK-8314884 - G1: Exclude eager reclaim candidates from marking
Relates :  
JDK-8276094 - JEP 423: Region Pinning for G1
Relates :  
JDK-8306541 - Refactor collection set candidate handling to prepare for JDK-8140326
Relates :  
JDK-8315502 - G1: Abort mixed phase if Prepare Mixed cleaned out all marking regions
Relates :  
JDK-7162317 - G1: Explicitly mark self-forwarded objects during marking cycles
Relates :  
JDK-8251288 - G1: Young gen sizing should take short-living humongous object allocation into account
Relates :  
JDK-8315686 - G1: Disallow evacuation of marking regions in a Prepare Mixed gc
Description
A common case in evacuation failure is that only a very small subset of the original contents of the region experiencing the failure is live.
We mark the region as old and basically completely full.

This is a waste of space. A following GC could clean them out cheaply in many cases.

May also be very interesting in case of pinned regions, i.e. clean the affected regions out in the next gc.
Comments
Changeset: 7e209528 Author: Thomas Schatzl <tschatzl@openjdk.org> Date: 2023-08-08 10:29:14 +0000 URL: https://git.openjdk.org/jdk/commit/7e209528d3690ff25f00efaa60bc10fadfb2c010
08-08-2023
A pull request was submitted for review. URL: https://git.openjdk.org/jdk/pull/14220 Date: 2023-05-30 14:00:30 +0000
31-05-2023
JDK-7162317 is an idea for special case handling for evac failure during marking.
18-05-2020