Re: Swap

[Dan Maas]

> >Yep. There's a reason for that: the kernel is *ALWAYS*
> >able to swap pages out to disk - even without "swap space".
> >Disabling swapspace simply forces the kernel to swap out
> >more code, since it cannot swap out any data.
>
> Sure ??? Where ?? What disk space uses it to swap pages to ?

The executables and binaries on your regular filesystems... Even with no
swap space, the kernel can "page out" (i.e. drop from memory) read-only file
mappings, since they can always be reloaded from disk if needed.

In other words, there is still a big difference between running without swap
space, and having every program do an mlockall() (which *really* forces all
pages to be permanently resident in RAM).

Still, it puzzles me why a system with no swap space would appear to be more
responsive than one with swap (assuming their working sets are quite a bit
smaller than total amount of RAM)... Can you do a controlled test somehow,
to rule out any sort of placebo effect?

Regards,
Dan