RFR: 8255716: AArch64: Regression: JVM crashes if manually offline a core

[Anton Kozlov]

On Mon, 2 Nov 2020 13:54:09 GMT, Patrick Zhang <qpzhang at openjdk.org> wrote:

>> Marked as reviewed by adinn (Reviewer).
>
> Thanks for your review and comments.

> @AntonKozlov If the code that sets the A53MAC property really needs to be based on the cpu count obtained from /proc/cpuinfo

I would like to know that for sure. The code was introduced in http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/6e2422a230fd#l6.48, unfortunately I don't know reasoning behind.

> Could you raise a new JIRA for that and propose a fix?

Ok, I'll do this, just to make sure we set the feature just as it was before.

@cnqpzhang I will likely re-introduce cpu_line counting in the follow-up patch. It would be handy if you just relax the assert (like `cpu_lines >= os::processor_count()`, btw, does this work for you, is the guess is correct?) instead of removing it completely. But this is not very important.
Also, I'm not a reviewer in the jdk project, not sure if I can be credited for review.

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PR: https://git.openjdk.java.net/jdk/pull/983