/dev/swap acting weird?

/dev/swap acting weird?

[philw]

>If my swap device is not big enough, will swapping still work?
Yes until is tries to page out into non-existant blocks
when the kernel will panic in executeio/swap.c

>>with the size of the swap partition. It is a
>>vector of reference counts used to mangae
>If it is much larger than the size reported by /dev/swap, will the 
>extra swap space be usable?
No. as I said, a reference count per page is required.
 

/dev/swap acting weird?

[Steve]

>the swap number in /dev/swap has nothing to do
>with the size of the swap partition. It is a
>vector of reference counts used to mangae
>page sharing on the disc. It is set by conf.nswap
>and is allocated by swapinit/swap.c at boot time.
>the number is reported so you can ensure the
>device used to swap onto is big enough.

If my swap device is not big enough, will swapping still work?
If it is much larger than the size reported by /dev/swap, will the 
extra swap space be usable?

/dev/swap acting weird?

[philw]

the swap number in /dev/swap has nothing to do
with the size of the swap partition. It is a
vector of reference counts used to mangae
page sharing on the disc. It is set by conf.nswap
and is allocated by swapinit/swap.c at boot time.
the number is reported so you can ensure the
device used to swap onto is big enough.

/dev/swap acting weird?

[Steve]

When my Magnum cpuserver boots, I don't have any swap configured.
At that time, here's what /dev/swap reports (I'm bootes on the console):

plan9% cat /dev/swap
304/4300 memory 0/19200 swap

I have 2 identical disks on this system, and I used disk/prep to create
a different sized swap partition on each one. However, when I use
the swap command to enable swapping to these devices, the 'total available'
field doesn't change at all:

plan9% ls -l /dev/sd*swap
--rw-rw-rw- w 0 bootes bootes 35225600 Sep 27 09:59 /dev/sd0swap
--rw-rw-rw- w 8 bootes bootes 67108864 Sep 27 09:59 /dev/sd1swap
plan9% swap /dev/sd0swap
swap: /dev/sd0swap
plan9%
plan9% cat /dev/swap
305/4300 memory 0/19200 swap
plan9%
plan9% swap /dev/sd1swap
swap: /dev/sd1swap
plan9% cat /dev/swap
305/4300 memory 0/19200 swap

I was expecting it to track the size of the swap partition in use.
Am I missing something?