RFR: 8257774: G1: Trigger collect when free region count drops below threshold to prevent evacuation failures [v7]

[Aditya Mandaleeka]

On Tue, 25 May 2021 15:57:48 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Aditya Mandaleeka has updated the pull request incrementally with two additional commits since the last revision:
>> 
>>  - Add G1 configuration option for proactive collections.
>>  - Minor indentation/formatting improvements.
>
> src/hotspot/share/gc/g1/g1_globals.hpp line 307:
> 
>> 305:           range(0.0, (double)max_uintx)                                     \
>> 306:                                                                             \
>> 307:   product(bool, G1AllowProactiveGC, true,                                   \
> 
> Imho this flag should be either an experimental or diagnostic flag. The reason is that it is only supposed to be used exclusively for troubleshooting, not giving generic guidelines for the collector (like e.g. MaxHeapSize).
> 
> This also avoids a CSR for this change.

Thanks @tschatzl, that makes sense to me. I'll push an update shortly that makes it a "diagnostic" flag.

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PR: https://git.openjdk.java.net/jdk/pull/3143