swap= parameter meanings.

Harvey J. Stein (abel@netvision.net.il)
Tue, 8 Apr 1997 21:26:39 +0300

I've been searching for documentation on the arguments for the swap
boot parameter. All I seem to find is the kernel source code. Does
anyone have/know of any documentation for the swap algorithm, and how
the swap= parameters affect it, or do I really just have to read the
kernel code to see what they do? Also, are they settable in a running
kernel (by writing to /proc/sys/vm/swapctl, for example)?

I'm looking for this because it seems to me like 2.0.29 is, under
certain conditions, not performing as well as 1.2.13 used to. This is
when running large apps which don't do much disk-i/o. When running
such apps, the kernel seems to still keep lots of ram tied up in disk
cache, which, I think, causes the large app to do more swapping than
it should have to. So, I wanted to fiddle around with the swap
parameters to see if changing this behavior would help. BTW, even in
the face of what seems to be massive disk activity, it's only the big
app which is slowing to a crawl. Other apps are still surprisingly
responsive, which is much better than I remember 1.2.13 being.


Harvey J. Stein
Berger Financial Research