/proc/sys/vm/freepages read-only?!?

["David L. Parsley" <parsley@linuxjedi.org>]

Hi,

I'm trying to do some vm tuning for diskless (and therefore swapless)
devices.  (I'm working on a distro that tftp's packages and runs
entirely in RAM)

Even on an X terminal with 64MB RAM, badly behaved apps can use lots of
ram in the Xserver, and what I'm seeing is a hang.  The box is usually
still pingable, just unresponsive.  I'm using cramfs pretty heavily, and
I think what's occuring is that the terminal gets too low on freepages,
and since pages used by X can't be swapped out, the box starts thrashing
the vm and is unable to get pages to uncompress into.

My first thought was echo (bigger numbers) > /proc/sys/vm/freepages -
but lo! - it's not writable anymore.  I found comments in page_alloc.c
indicating it had to be read-only, but it seems it's only a safety
precaution.  Something along the lines of values too small being 'bad
bad'.


help?
	David
-- 
David L. Parsley
Network Administrator
Roanoke College