RFR (M): Optimize object/array marking with bit-stealing task encoding

[Aleksey Shipilev]

On 01/16/2017 05:06 PM, Roman Kennke wrote:
> Excellent!
> 
> '512TB ought to be enough for anybody' ? ;-)

Yes, was shooting for 1 PB first:
  https://twitter.com/shipilev/status/819279445613809664

...but then I needed 5 bits for power, and at least 10 bits for chunks. Because
I believe we will reach 1024 threads much faster than 512 TB :) With some
effort, we could make chunks counted in ObjArrayMarkingStrides, and then
enforcing OAMS > 2^16 would enable us to use 4 bits for power. But that
complicates the code quite a bit, so I gave up.

Thanks,
-Aleksey