RFR: 8303252: G1: Return early from Full-GC if no regions are selected for compaction. [v3]

[Ivan Walulya]

On Tue, 28 Feb 2023 19:25:11 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> src/hotspot/share/gc/g1/g1FullCollector.cpp line 334:
>> 
>>> 332: 
>>> 333:   if (!has_compaction_targets()) {
>>> 334:     return;
>> 
>> Maybe it is useful to add a log message here that no compaction targets were found before exiting. Something like:
>> 
>> log_debug(gc, phases) debug("Phase 2: No compaction targetes");
>> 
>> So that people looking at logs have a better understanding why the other phases are skipped and the next log message will be about phase 5.
>
> Wouldn't `log_info(gc, phases) ("No Regions selected for compaction.` above (on the info level) already cover this?

It is fine for me either way, can keep both or leave just the log_info.

-------------

PR: https://git.openjdk.org/jdk/pull/12768