RFR: 8247179: Mechanism for VM operations to not take part in safepoint coalescing
erik.osterlund at oracle.com
Fri Jun 12 07:41:39 UTC 2020
When we have a chain of safepoint operations, we coalesce them to run in
a single safepoint operation.
Today that is fine, but in the near future, there will be a need for
certain safepoint operations (my GC safepoints) to not be coalesced to
run together with other safepoint operations.
The reason relates to concurrent stack scanning, and there are more
details about the rationale in the bug comments.
I also cleaned up the nested looping when evaluating VM operations in
safepoints, to be a single loop. I found it unnecessarily hard to deal
with the nested loop logic.
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