RFR: 8251463: Obsolete -XX:ForceNUMA option

[Kim Barrett]

> On Aug 14, 2020, at 2:36 PM, Albert Yang <albert.m.yang at oracle.com> wrote:
> 
> 
> Hi,
> 
> I am not really sure about the change in `os_windows.cpp`. With `ForceNUMA` gone, it seems that NUMA will be completely disabled on Windows.
> 
> https://bugs.openjdk.java.net/browse/JDK-8251463
> http://cr.openjdk.java.net/~ayang/webrevs/webrev/

See JDK-8244065 Implement NUMA support in Windows
Currently going nowhere.

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src/hotspot/os/windows/os_windows.cpp
4240   if (UseNUMAInterleaving || (UseNUMA && FLAG_IS_DEFAULT(UseNUMAInterleaving))) {
=>
4238   if (UseNUMAInterleaving) {

I think this line should not be changed.  It's true that we currently
unconditionally set UseNUMA = false above, but that's because NUMA
support is incomplete on Windows.  If it were to be completed and
UseNUMA could remain true then we'd want the original version of this.
Probably.  Depending on what finishing NUMA support ends up looking
like.  But that's the present best guess.

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