RFR: Add regular regions to free set after partial GC

[Zhengyu Gu]

Good to me.

-Zhengyu

On 08/24/2017 01:54 PM, Aleksey Shipilev wrote:
> On 08/24/2017 07:32 PM, Aleksey Shipilev wrote:
>> This is the leftover from LRU/Generational work. It was deemed necessary to avoid allocating in
>> non-empty regions to keep allocation timestamps in order. After some discussion, it seems that we
>> can still allocate in regular regions after partial GC.
>>
>> Now, the tricky part is that we have to still add root regions to _root_regions, otherwise
>> everything breaks. Note that this fix means root regions are in free set, which means we could
>> evacuate objects from cset to root regions. I think this is not problematic -- it fact, preferring
>> root regions over other reduces heap connectedness?
> 
> Complication: we need to bound the root region scan at its latest top:
>    http://cr.openjdk.java.net/~shade/shenandoah/partial-root-free/webrev.01/
> 
> -Aleksey
>