RFR: 8338737: Shenandoah: Reset marking bitmaps after the cycle

[Xiaolong Peng]

On Thu, 17 Oct 2024 21:36:51 GMT, Xiaolong Peng <xpeng at openjdk.org> wrote:

>> src/hotspot/share/gc/shenandoah/shenandoahGeneration.cpp line 235:
>> 
>>> 233:   if (need_bitmap_reset()) {
>>> 234:     if (heap->mode()->is_generational() && is_global() && !heap->young_generation()->need_bitmap_reset()) {
>>> 235:       //Only need to reset bitmap for old generation.
>> 
>> I'd like to see an assert here that all the bitmaps for all the young regions are already clear.
>
> I'll add it, thanks.

My understanding is: op_reset_after_collect is called at the end of a successful collection after the old region (A) is repurposed as a young region, if so it is not an issue, I'll double confirm.

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/516#discussion_r1805478665