RFR: Add generations to freeset [v5]

[Aleksey Shipilev]

On Thu, 13 Apr 2023 11:01:40 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Remove debug instrumentation
>
> src/hotspot/share/gc/shenandoah/shenandoahFreeSet.cpp line 65:
> 
>> 63:   assert (idx < _max, "index is sane: " SIZE_FORMAT " < " SIZE_FORMAT " (left: " SIZE_FORMAT ", right: " SIZE_FORMAT ")",
>> 64:           idx, _max, _mutator_leftmost, _mutator_rightmost);
>> 65:   assert(!_mutator_free_bitmap.at(idx) || (alloc_capacity(ShenandoahHeap::heap()->get_region(idx)) > 0),
> 
> Things like `(alloc_capacity(ShenandoahHeap::heap()->get_region(idx)) > 0)` are used often here, might just use a separate method for it.

Also, for the benefit of fastdebug builds performance (= faster testing), this can be something like:


bool is_free = _mutator_free_bitmap.at(idx);
assert(!is_free || has_alloc_capacity(idx), "Mutator free set should contain useful regions");
return is_free;

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

PR Review Comment: https://git.openjdk.org/shenandoah/pull/250#discussion_r1165366829