JDK-8368740 : Serial: Swap eden and survivor spaces position in young generation
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2025-09-26
  • Updated: 2025-12-03
  • Resolved: 2025-10-16
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JDK 26
26 b21Fixed
Related Reports
Causes :  
JDK-8372993 - Serial: max_eden_size is too small after JDK-8368740
Causes :  
JDK-8370198 - Test gc/arguments/TestShrinkHeapInSteps.java crashed: assert(left >= right) failed: avoid underflow
Duplicate :  
JDK-8368191 - GC tests LinearListLow and CircularListLow fail due to OutOfMemoryError with SerialGC
Relates :  
JDK-8338977 - Parallel: Improve heap resizing heuristics
Sub Tasks
JDK-8369810 :  
Release Note: Serial: Expand Eden Space Beyond SurvivorRatio - Open
Description
There are 3 spaces inside young-gen, eden, from, and to spaces. (The latter two are survivor spaces.)

Eden is placed before from/to. This placement makes is hard to expand eden when there is live objs inside from/to spaces. Therefore, one can encounter premature OOM, even when there are still large unused room at the end of young-gen.

One can move eden after from/to spaces so that eden can expand to the end of young-gen in order to satisfy an allocation request.

The same layout is also used in Parallel since JDK-8338977.
Comments
Changeset: 1392a0b4 Branch: master Author: Albert Mingkun Yang <ayang@openjdk.org> Date: 2025-10-16 19:55:07 +0000 URL: https://git.openjdk.org/jdk/commit/1392a0b4608f6196f207fcebbab75b2d79fdc758
16-10-2025
A pull request was submitted for review. Branch: master URL: https://git.openjdk.org/jdk/pull/27513 Date: 2025-09-26 07:33:19 +0000
26-09-2025