RFR(XL): 8220310: Implementation: NUMA-Aware Memory Allocation for G1, Mutator (1/3)

[Kim Barrett]

> On Oct 29, 2019, at 4:39 PM, sangheon.kim at oracle.com wrote:
> 
> Hi Kim and Per,
> 
> Thanks for your reviews.
> 
> -----------
> To all reviewers,
> 
> Stefan suggested a safer handling of node index so here's another webrev.
> Basically when we enable AlwaysPreTouch, we expect to get actual node id of the address.
> However, in theory we still may get something unknown id. So below change is added to have safer handling of node index.
> 
> uint G1NUMA::index_for_region(HeapRegion* hr) const {
>   if (!is_enabled()) {
>     return 0;
>   }
> 
> 
>    if (AlwaysPreTouch) {
>      // If we already pretouched, we can check actual node index here.
> -  return index_of_address(hr->bottom());
> 
> +    // However, if node index is still unknown, use preferred node index.
> +    uint node_index = index_of_address(hr->bottom());
> +    if (node_index != UnknownNodeIndex) {
> +      return node_index;
> +    }
> 
> Webrev:
> http://cr.openjdk.java.net/~sangheki/8220310/webrev.8
> http://cr.openjdk.java.net/~sangheki/8220310/webrev.8.inc
> Testing: local build

Looks good.