RFR(S): 8160064: StackWalker implementation added logging option without using UL

[David Holmes]

Hi Rachel,

On 28/09/2016 5:47 AM, Rachel Protacio wrote:
> Hi,
>
> Please review this small fix correcting the StackWalker print output
> mechanism by moving it to Unified Logging. Includes a new jtreg test,
> and passes JPRT.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8160064
> Open webrev: http://cr.openjdk.java.net/~rprotacio/8160064/

Was there a specific reason to make this available in product rather 
than just "develop" as the existing flag was?

       if (!ShowHiddenFrames && (skip_hidden_frames(mode) || 
get_caller_class(mode))) {
         if (method->is_hidden()) {
!         {
!           ResourceMark rm;
!           outputStream* st = Log(stackwalk)::trace_stream();

This should check if logging is enabled before potentially wasting time 
on the ResourceMark etc. Ditto for other places. Did you revert this due 
to Coleen's query? We want to minimise what happens when logging is not 
enabled - ideally it would be 100% free.

I also query why all the logging entries are at the trace level?

Thanks,
David

> Thank you!
> Rachel