RFR: Non-cancellable mark loops should have sensible stride

[Aleksey Shipilev]

On 07/05/2018 09:38 AM, Roman Kennke wrote:
> It looks ok. But why did we do it in the first place? It looks like this
> was done on purpose. But it also seems illogical. Can you hg annotate it
> and see how that happened?

We did this to match the old code while refactoring mark_loop. Our intent was to compile down the
strided marking loop to the same "process one element, check for termination" shape we used to have.
But that is nonsensical, and performance data shows it really does not make sense.

-Aleksey