RFR: 8273300: Check Mutex ranking during a safepoint

Fri Sep 10 16:23:53 UTC 2021

On Fri, 10 Sep 2021 15:23:49 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

> This change checks lock ranking during a safepoint.  For some reason, safepoint checking was excluded, probably from the days where Safepoint_lock and Threads_lock were used.
> Because of checking during a safepoint, some locks had to get lower ranks.  The CR has the details of which locks these were.  The Service_lock complicates things because it's held during oops_do, which may take out other G1 locks.
> This was built and tested with Shenandoah.  Thanks to @zhengyu123 for the changes in Shenandoah.
> Tests run tier1-8.

Looks good.

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Marked as reviewed by eosterlund (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5467