RFR: JDK-8315478: GenShen: Tolerate round-off errors in preselected promotion budget

[Y. Srinivas Ramakrishna]

On Fri, 1 Sep 2023 16:33:20 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

> An assert failure identified an error in previous implementation.  See JBS ticket for description of issue and reproducer.

src/hotspot/share/gc/shenandoah/shenandoahGeneration.cpp line 409:

> 407: 
> 408:   assert(old_available >= old_consumed, "Cannot consume (" SIZE_FORMAT ") more than is available (" SIZE_FORMAT ")",
> 409:          old_consumed, old_available);

So you are just adding debugging code to catch the issue more easily? (as well as the change further below)

I don't see any change in the control flow or the state here.

Is the intention to add this change and the one below to aid debugging of a very difficult to reproduce problem?

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/317#discussion_r1313661996