RFR: 8261160: Add a deserialization JFR event [v2]

[Chris Hegarty]

On Thu, 11 Feb 2021 14:27:19 GMT, Roger Riggs <rriggs at openjdk.org> wrote:

>> Marked as reviewed by rriggs (Reviewer).
>
> As proposed, events are only created if there is a serialFilter in effect (and enabled by JFR configuration).
> Being able to create the events without a serialFilter in effect would be useful for monitoring, especially if it could be controlled by a separate JFR configuration option.  (always, never, serial-filter , etc.)

I updated the PR and addressed all comments so far. Specifically:

@RogerRiggs The generation of the event is independent of whether the filter is set or not.  I also added a piece of state to determine if a filter is set or not. I think it could be useful to analyse all Deserialisation events to, say, ensure that there are none operating without a filter ( and the `filterStatus` state is ambitious in the `null` case ).

@coffeys I would like GlobalFilterTest to run regardless of whether or not the jfr module is present, but of course running the test with jfr enabled is desirable too, so I added a separate at test tag for that case.

@egahlin Excellent suggestions on the naming, etc. I adopted all.  And added a test to ensure that the creation and generation of the event does not inadvertently trigger class initialization if the filter rejects the attempt ( thanks @dfuch )

@dfuch Thanks for the improved label suggestion, it is now merged in.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2479