User-mode Linux kernel port

Hi,

this question is not UML-kernel specific, sorry. :)

I'm doing some UML's whith mem=32M and I wouldn't like the disk cache to 
eat all the memory, as it does:

debian:~# free
              total       used       free     shared    buffers     cached
Mem:         30016      28272       1744          0       1812      18720
-/+ buffers/cache:       7740      22276
Swap:        32760       3164      29596

This is duplicated disk cache because the main host (the real server) is 
already cacheing this pages. I know that this is good for "host" servers 
but here is just a waste and I don't have memory to waste :)

Did anyone manage to reduce the disk cache in the UML?

/usr/src/Documentation/filesystems/proc.txt is outdated and refers to 
files that don't exist. Trying to play with /proc/sys/vm/* makes no 
change to UML's memory.

Any hints?

Thanks in advance,
Nuno Silva

Thanks for the quick reply Jeff.

If I run uml_net suid root doesn't that satisfy the condition of root priv
to use ethertap, since the UML instance doesn't (directly) touch the
ethertap device? If I am not mistaken, doesn't the UML instance merely use
an FD to exchange packets that are bound to the ethertap device, where
uml_net acts a proxy?

- Rod

On Tue, 27 Aug 2002, Jeff Dike wrote:

> rodlist@... said:
> > It therefore appears that the UML instance does require root priv for
> > some /proc or /dev access, yet I can't seem to find out what it is.
> > Any ideas?
>
> Don't use ethertap.  It isn't usable if you can't have root privileges.
>
> Use TUN/TAP instead.
>
> 				Jeff
>
>