RFR: 8364081: Shenandoah & GenShen logging improvement [v3]

[Y. Srinivas Ramakrishna]

On Mon, 28 Jul 2025 16:56:40 GMT, Rui Li <duke at openjdk.org> wrote:

>> Fix missing `increment_total_collections` usages in Shenandoah (otherwise, the invocation count is always 0 as shown in https://github.com/openjdk/jdk/pull/26272 overview). 
>> 
>> Also added some generational information for generational shenandoah logging.
>> 
>> Shenandoah logging samples:
>> 
>> 
>> ######################
>> Shenandoah - Before GC
>> ######################
>> [0.161s][debug][gc,heap      ] GC(0) Heap Before GC invocations=0 (full 0):
>> [0.161s][debug][gc,heap      ] GC(0)  Shenandoah Heap
>> [0.161s][debug][gc,heap      ] GC(0)    100M max, 100M soft max, 100M committed, 40312K used
>> [0.161s][debug][gc,heap      ] GC(0)   400 x 256K regions
>> [0.161s][debug][gc,heap      ] GC(0)  Status: not cancelled
>> [0.161s][debug][gc,heap      ] GC(0)  Reserved region:
>> [0.161s][debug][gc,heap      ] GC(0)   - [0x00000000f9c00000, 0x0000000100000000) 
>> [0.161s][debug][gc,heap      ] GC(0)  Collection set:
>> [0.161s][debug][gc,heap      ] GC(0)   - map (vanilla): 0x0000000000004e70
>> [0.161s][debug][gc,heap      ] GC(0)   - map (biased):  0x0000000000001000
>> [0.161s][debug][gc,heap      ] GC(0) 
>> [0.161s][debug][gc,metaspace ] GC(0) Metaspace Before GC invocations=0 (full 0):
>> [0.161s][debug][gc,metaspace ] GC(0)  Metaspace       used 86K, committed 320K, reserved 1114112K
>> [0.161s][debug][gc,metaspace ] GC(0)   class space    used 3K, committed 128K, reserved 1048576K
>> 
>> ######################
>> Shenandoah - After GC
>> ######################
>> [2.179s][debug][gc,heap        ] GC(9) Heap After GC invocations=17 (full 7):
>> [2.179s][debug][gc,heap        ] GC(9)  Shenandoah Heap
>> [2.179s][debug][gc,heap        ] GC(9)    100M max, 100M soft max, 100M committed, 97113K used
>> [2.179s][debug][gc,heap        ] GC(9)   400 x 256K regions
>> [2.179s][debug][gc,heap        ] GC(9)  Status: not cancelled
>> [2.179s][debug][gc,heap        ] GC(9)  Reserved region:
>> [2.179s][debug][gc,heap        ] GC(9)   - [0x00000000f9c00000, 0x0000000100000000) 
>> [2.179s][debug][gc,heap        ] GC(9)  Collection set:
>> [2.179s][debug][gc,heap        ] GC(9)   - map (vanilla): 0x0000000000004e70
>> [2.179s][debug][gc,heap        ] GC(9)   - map (biased):  0x0000000000001000
>> [2.179s][debug][gc,heap        ] GC(9) 
>> [2.179s][debug][gc,metaspace   ] GC(9) Metaspace After GC invocations=17 (full 7):
>> [2.179s][debug][gc,metaspace   ] GC(9)  Metaspace       used 125K, committed 320K, reserved 1114112K
>> [2.179s][debug][gc,metaspace   ] GC(9)   class space    used 4K, commi...
>
> Rui Li has updated the pull request incrementally with one additional commit since the last revision:
> 
>   const & print

Marked as reviewed by ysr (Reviewer).

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

PR Review: https://git.openjdk.org/jdk/pull/26469#pullrequestreview-3064549890