Check the default huge page size for Linux

[hankluo6]

In Linux, we can read /proc/meminfo to get the huge page size.

Please node that this will get only one possible size, but Linux can supports more than one huge page size.

[daanx]

Thanks for the PR! and apologies for being so late addressing this :-(.
But yikes -- this is so fragile; very hesitant to include this ... it may be the only way to get the large page size though so perhaps it is what it is :-). I need to think a bit more on this.