RFR: 8327097: GenShen: Align PLAB sizes down rather than up [v6]

[Kelvin Nilsen]

On Wed, 20 Mar 2024 22:57:30 GMT, Y. Srinivas Ramakrishna <ysr at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Add comments to clarify behavior of retire_plab
>
> src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp line 1124:
> 
>> 1122:   assert(is_aligned(future_size, CardTable::card_size_in_words()),
>> 1123:          "Align by design, future_size: " SIZE_FORMAT ", card_size: " SIZE_FORMAT ", max_size: " SIZE_FORMAT,
>> 1124:          future_size, (size_t) CardTable::card_size_in_words(), generational_heap->plab_max_size());
> 
> More succinct:
> 
> const size_t future_size = MIN2(cur_size*2, generational_heap->plab_max_size());
> ...

Thanks.  Done.

> src/hotspot/share/gc/shenandoah/shenandoahHeap.cpp line 1211:
> 
>> 1209:     unexpend_promoted(not_promoted);
>> 1210:   }
>> 1211:   size_t original_waste = plab->waste();
> 
> const

Thanks.  Done.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/401#discussion_r1535996298
PR Review Comment: https://git.openjdk.org/shenandoah/pull/401#discussion_r1535997096