DVD blockdevice buffers

[Eduard Hasenleithner]

I have a problem with the buffering mechanism of my blockdevice,
namely a ide_scsi DVD-ROM drive. After inserting a DVD and reading
data linearly from the DVD, an excessive amount of buffer memory gets
allocated.

This can easily be reproduced with
	cat /dev/sr0 > /dev/null

Remember, nearly the same task is carried out when playing a DVD.

As a result the system performance goes down. I'm still able to use
my applications, but es every single piece of unused memory is swapped
out, and swapping in costs a certain amount of time.

So, what wents wrong? I tried to find some information on this with
google and geocrawler, but i didn't have a success :(

Kernel: linux-2.4.4

hoping for some tips ...

-- 
Eduard Hasenleithner
student of
Salzburg University of Applied Sciences and Technologies