review(XXS): 7041501: NUMA: Expand the old gen more aggressively

[Igor Veresov]

With UseNUMA we prescribe the OS to allocate the pages round-robin in 
the old gen. But the default expansion rate is quite low (128K in 32bit, 
167K in 64bit), less than a typical large page (in this case the 
expansion delta is rounded to the size of the page). This renders the RR 
allocation attribute useless, because we ask the OS to do it for a 
single page. The solution is to increase the expansion rate when UseNUMA 
is specified (I made it 64M). Also, we should make sure that the delta 
is not less than page_size * lgroup_num, which will come into play with 
really huge pages.

Thanks to Tom Deneau for noticing the problem!

Webrev: http://cr.openjdk.java.net/~iveresov/7041501/webrev.00/

igor