RFR: Extend documentation regarding logging [v5]

[David Holmes]

On Wed, 7 Dec 2022 05:34:13 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Johan Sjölen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove another line break
>
> src/guide/hotspot-development.md line 21:
> 
>> 19: ~~~
>> 20: 
>> 21: Where 'gc' and 'marking' are tags, and 'info' is the log level. Tags associate log messages with certain subsystems or features and the log level determines the importance and verbosity of the message. The most verbose output is trace, and the least is error. The full list of tags is available [here](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/logging/logTag.hpp) and the full list of levels [here](https://github.com/openjdk/jdk/blob/master/src/hotspot/share/logging/logLevel.hpp).
> 
> The full list of tags for a given VM is found from running `java -Xlog:help`.

I still think this is a better source of information than the repo files. You often want to know what logging is available in the specific jvm you are running and can't necessarily figure out how to get to the right source file for that.

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PR: https://git.openjdk.org/guide/pull/91