RFR(s): 8151264: Add a notification mechanism for UL configuration changes

[Robbin Ehn]

Thanks David for looking at this.

On 03/10/2016 11:19 AM, David Holmes wrote:
> Hi Robbin,
>
> On 9/03/2016 7:02 PM, Robbin Ehn wrote:
>>
>> Hi, please review this minor change.
>
> A notification mechanism is not so minor - what are the programming
> rules for the callbacks? which threads might execute them? Are there any
> obvious deadlock/livelock potentials? Do we need to unregister a callback?
>
> At a minimum there should be some comments regarding the nature of the
> callback and what it can and can't do.

Yes, I will document it better.

>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8151264/
>> Webrev: http://cr.openjdk.java.net/~rehn/8151264/webrev/
>
> Some minor nits:
>
> src/share/vm/logging/log.cpp
>
> Copyright needs 2016 added.
>
> ---
>
> src/share/vm/logging/logConfiguration.cpp
>
> +   assert(cb != NULL, "Should not initialize register NULL as listener.");
>
> "initialize register" doesn't make grammatical sense - delete "initialize"
>
> +   for (size_t i=0;i<_n_listener_callbacks;i++) {
>
> Style nits: spaces around operators and after ;
>
> ---
>
> src/share/vm/logging/logConfiguration.hpp
>
> +   // After any configuration change this method should be called by in
> scope of LogConfigurationLock
>
> Delete 'by' - or may I suggest:
>
> // This should be called after any configuration change while still
> holding ConfigurationLock
>

Yes, thanks!

/Robbin

> Thanks,
> David
> -----
>
>> Tested with a new internal vm test (included).
>>
>> Thanks!
>>
>> /Robbin