[8u] RFR: 8215727: Restore JFR thread sampler loop to old / previous behavior

[Jaroslav Bachorík]

Hi Ekaterina,

the change looks good. Not a reviewer, though.

Cheers,

-JB-

On Fri, Jul 24, 2020 at 9:43 AM Ekaterina Vergizova <katya at azul.com> wrote:
>
> Hello,
> I would like to backport JFR issue 8215727 to 8u.
>
> JBS: https://bugs.openjdk.java.net/browse/JDK-8215727
> Original patch: https://hg.openjdk.java.net/jdk/jdk/rev/58154bf80f90
> Webrev for 8u: https://cr.openjdk.java.net/~apetushkov/jfr_backports_katya/8215727/webrev.00/
>
> The patch applies almost cleanly except for the third hunk of jfrThreadSampler.cpp.
> It doesn't apply due to different context (iterating through java threads is different between 8u and 13), re-applied manually.
>
> Tested with tier1 and jdk.jfr tests on Linux and Windows, no regression.
>
> Thanks,
> Ekaterina
>