JDK-8267836 : Separate eager reclaim remembered set threshold from G1RSetSparseRegionEntries
  • Type: Enhancement
  • Component: hotspot
  • Sub-Component: gc
  • Affected Version: 17
  • Priority: P4
  • Status: Resolved
  • Resolution: Fixed
  • Submitted: 2021-05-27
  • Updated: 2021-06-07
  • Resolved: 2021-06-02
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JDK 17
17 b25Fixed
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Description
Currently the remembered set eager reclaim threshold is based on G1RSetSparseRegionEntries. I.e. otherwise eligible humongous objects are only considered candidates for eager reclaim if their remembered set has less than G1RSetSparseRegionEntries entries.

The reason for this limitation has been that before JDK-8233919 (in JDK14) it has been very expensive to get a remembered set size estimate if the remembered set for that heap region had expanded to fine tables.

This is not the case any more, and there are situation where you want to set this threshold (much) larger than the number of sparse table entries.

By default, this new value should still be based on the current value.
Comments
Changeset: 2d494bff Author: Thomas Schatzl <tschatzl@openjdk.org> Date: 2021-06-02 09:31:59 +0000 URL: https://git.openjdk.java.net/jdk/commit/2d494bffffd532be0b5d2c17495d705f925932e7
02-06-2021