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

[Rachel Protacio]

Hi,


On 9/27/2016 6:54 PM, David Holmes wrote:
> 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?
No, that was entirely my mistake. I didn't notice it was a develop flag. 
Will update that.
>
>       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.
Thanks for pointing that out. Will put in checks.
>
> I also query why all the logging entries are at the trace level?
Will address at tip of thread...
Rachel
>
> Thanks,
> David
>
>> Thank you!
>> Rachel