RFR: 8345750: Shenandoah: Test TestJcmdHeapDump.java#aggressive intermittent assert(gc_cause() == GCCause::_no_gc) failed: Over-writing cause

[Kelvin Nilsen]

On Fri, 17 Jan 2025 23:12:14 GMT, William Kemper <wkemper at openjdk.org> wrote:

> This occurs when an attempt to produce a heap dump conflicts with a concurrent cycle. The heap dump vm operation attempts to run a cycle directly on the VM thread with no regard for the state of the concurrent collection. Although Shenandoah _is_ technically capable of running an entire _full_ GCs on the vm thread, I would rather not add another dependency on full GCs, nor would I like to cancel an in-progress concurrent GC. Instead, Shenandoah will follow the pattern established ZGC in which the calling thread waits for a concurrent cycle to complete before taking the heap dump.

Thanks for handling this.

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Marked as reviewed by kdnilsen (Author).

PR Review: https://git.openjdk.org/jdk/pull/23186#pullrequestreview-2560162856