[11u] RFR: 8257602: Introduce JFR Event Throttling and new jdk.ObjectAllocationSample event (enabled by default)

[Jaroslav Bachorík]

Greetings,

The original attempt to generate webrev from two changesets failed
miserably. Therefore I am updating the webrev links as follows:
* Main issue: http://cr.openjdk.java.net/~jbachorik/8257602/jdk11/00/webrev/
* Followup AIX build fix:
https://cr.openjdk.java.net/~jbachorik/8258094/jdk11/00/webrev/

Regards,

-JB-

On Tue, Dec 15, 2020 at 9:21 AM Jaroslav Bachorík
<jaroslav.bachorik at datadoghq.com> wrote:
>
> Greetings,
>
> I would like to ask for review of this JDK11u backport patch:
>
> Issue   :  https://bugs.openjdk.java.net/browse/JDK-8257602
> Webrev: http://cr.openjdk.java.net/~jbachorik/8257602/jdk11/00/webrev/
>
> The webrev contains the main change backported from JDK-8257602 and
> the followup patch for AIX build failure resolved as JDK-8258094. I
> decided to roll both changesets into one webrev to get a fully
> buildable system once this backport request is approved.
>
> The original changeset of JDK-8257602 had to be slightly adjusted for
> the following:
> * hunk offsets not matching because of larger structural changes
>    resolution: the appropriate code was inserted manually
> * missing Atomic::load_acquire and Atomic::release_store functions
>    resolution: used OrderAccess::* equivalents
> * different argument order for Atomic::cmpxchg and Atomic::store
>    resolution: modified the call-site argument order to match what is
> provided by Atomic::*
> * [test] missing support for event streaming
>    resolution: used the recording in non-streaming mode while keeping
> the test semantics
>
> All tier1, tier2 and jdk_jfr tests are passing with the changes applied.
>
> Cheers,
>
> -JB-