Bug ID: JDK-8240556 Abort concurrent mark after effective eager reclamation of humongous objects

JDK-8240556 : Abort concurrent mark after effective eager reclamation of humongous objects

Type: Enhancement
Component: hotspot
Sub-Component: gc
Affected Version: 15

Priority: P4
Status: Resolved
Resolution: Fixed

Submitted: 2020-03-05
Updated: 2025-10-16
Resolved: 2020-09-25

Versions (Unresolved/Resolved/Fixed)

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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.

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JDK 16
16 b18Fixed

Related Reports

Blocks :	JDK-8248783 - G1: Trigger concurrent start if humongous allocation needs the reserved space to avoid evac failure
Blocks :	JDK-8253177 - outputStream not declared in markWord.hpp
Blocks :	JDK-8248221 - G1: millis_since_last_gc updated at wrong time
Blocks :	JDK-8247928 - Refactor G1ConcurrentMarkThread for mark abort
Relates :	JDK-8316355 - G1: Improve concurrent undo cycle to be more efficient
Relates :	JDK-8242847 - G1 should not clear mark bitmaps with no marks
Relates :	JDK-8253928 - G1: Remove G1ConcurrentMarkThread::set_in_progress declaration
Relates :	JDK-8248917 - G1: Reconsider counting aborted concurrent marks as full collections
Relates :	JDK-8253902 - G1: Starting a new marking cycle before the conc mark thread fully completed causes assertion failure
Relates :	JDK-8245511 - G1 adaptive IHOP does not account for reclamation of humongous objects by young GC
Relates :	JDK-8265326 - Strange Characters in G1GC GC Log

Description

Sometimes humongous allocations could trigger excessive concurrent mark cycles, although young-gen collections already reclaim many humongous objects with eager reclamation.
G1 could abort such unnecessary concurrent mark cycles in such cases.

See discussions in:
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2020-January/028357.html
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2020-March/028712.html

Comments

Changeset: 37b70282 Author: Thomas Schatzl <tschatzl@openjdk.org> Date: 2020-09-25 07:11:55 +0000 URL: https://git.openjdk.java.net/jdk/commit/37b70282

25-09-2020