RFC: Throughput barriers for G1

[Thomas Schatzl]

Hi all,

  just one comment:

On Wed, 2016-11-09 at 16:11 +0100, Erik Helin wrote:
> Hi all,
> 
> [...]
> 
> The responsibility of the post-write barrier is to queue up pointers 
> between regions so that the concurrent refinements threads can update
> the remembered sets concurrently.  If you were to give up this, an 
> alternative post-write barrier could look like:
> 
> if (y != NULL) {
>    if (card(o.x) == Clean) {
>        card(o.x) = Dirty;
>    }
> }
> 

Actually, one can simply reuse all the existing post-write barrier code
generation and optimizations from any of the other collectors in the
simplest case.

I do not think parallel GC performs the NULL check :)

Thanks,
  Thomas