[TrouSerS-tech] Notes about mlock for Linux

[Wyllys I. <Wyllys.Ingersoll@Sun.COM>]

I found this on the Ubuntu manpage for "mlock":

...
  Linux Notes
        Under Linux, mlock() and munlock() automatically round addr down to the
        nearest  page boundary.  However, POSIX.1-2001 allows an implementation
        to require that addr is page aligned, so portable  applications  should
        ensure this.
...

So, while it appears that it is probably safe to NOT worry about alignment on
Linux, it doesn't hurt to ensure it.

The code I submitted ensures the alignment for Solaris, but will fail on Linux
because some of the macros are not defined.  I can fix it, though.  Once you
know PAGESIZE, it is easy to compute PAGEOFFSET and PAGEMASK.  I will work up
a new patch and submit one that will compile under Linux as well.

-Wyllys