Integrated: 8300915: G1: incomplete SATB because nmethod entry barriers don't get armed

[Richard Reingruber]

On Wed, 25 Jan 2023 13:32:27 GMT, Richard Reingruber <rrich at openjdk.org> wrote:

> The change makes sure all nmethod entry barriers are armed when a G1 concurrent marking cycle starts by doing it unconditionally in `G1ConcurrentMark::pre_concurrent_start()`. The barrier is needed to add oop constants to the SATB.
> 
> This alone would be a conservative/minimal fix but I didn't like that `CodeCache::is_gc_marking_cycle_active()` can return true after a marking cycle start is undone. I.e. `G1ConcurrentMarkThread::_state == Idle && CodeCache::is_gc_marking_cycle_active()` is possible.
> Edit: It felt like an inconsistency but maybe its actually ok not to finish the CC marking cycle when the G1 marking is undone. Please comment...
> The changes in `G1ConcurrentMark::post_concurrent_undo_start()` were made to avoid it.
> 
> 
> Testing
> 
> * Rebased this PR onto [JDK-8297487](https://bugs.openjdk.org/browse/JDK-8297487), replaced related assertions with guarantees, and then executed test/langtools:tier1 in a loop for 12h without seeing the issues reported in [JDK-8299956](https://bugs.openjdk.org/browse/JDK-8299956).
> 
> * CI testing at SAP: This includes most JCK and JTREG tiers 1-4, also in Xcomp mode, on the standard platforms and also on ppc64le.
> 
> * GHA: build failures because download of apache ant failed. `serviceability/jvmti/vthread/SuspendResumeAll/SuspendResumeAll.java` had a timeout on windows-x64. Should be unrelated. It succeeded in our CI testing.

This pull request has now been integrated.

Changeset: 3db558b6
Author:    Richard Reingruber <rrich at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/3db558b67bebfe559833331475f481c588147084
Stats:     35 lines in 5 files changed: 20 ins; 10 del; 5 mod

8300915: G1: incomplete SATB because nmethod entry barriers don't get armed

Reviewed-by: tschatzl, eosterlund

-------------

PR: https://git.openjdk.org/jdk/pull/12194