On 12/4/2017 7:49 PM, Dave Horsfall wrote:
> On Mon, 4 Dec 2017, Warner Losh wrote:
>
> [ Swap files ]
>
>> Pages are pages. The filesystem handles the details for the offset of 
>> each one. There's no contiguous on disk requirement.
>
> I've used at least one *ix OS that required it be both contiguous and 
> pre-allocated; Slowaris?
>
Nope, unless mkfile is is guaranteed to give you contiguous space:

# uname -a
SunOS vmsol8 5.8 Generic_108529-05 i86pc i386 i86pc
# mkfile 100m a.a
# swap -a /a.a
# swap -l
swapfile             dev  swaplo blocks   free
/dev/dsk/c0d0s1     102,1       8 1048936 1048896
/a.a                  -        8 204792 204792