RFR: JDK-8066441 - Add PLAB trace event

[Erik Helin]

On 2014-12-02, Staffan Friberg wrote:
> Hi,
> 
> As noted in the original thread [1] about this event we split up the commit
> in 4 different steps. This is the first step that only adds the event and
> methods to send them, but the usage will be added separately for the 3 GCs
> using PLABs.
> 
> Bug (sub-task): https://bugs.openjdk.java.net/browse/JDK-8066441
> Webrev: http://cr.openjdk.java.net/~sfriberg/JDK-8066441/webrev.00

Looks good, Reviewed.

Thanks,
Erik

> Thanks,
> Staffan
> 
> [1] - (RFR: JDK-8055845 - Add trace event for promoted objects) - http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2014-December/011477.html
>