Re: VM: qsbench numbers

[Linus Torvalds]

On Sun, 4 Nov 2001, Lorenzo Allegrucci wrote:
>
> I begin with the last Linus' kernel, three runs and kswapd CPU
> time appended.

It's interesting how your numbers decrease with more swap-space. That,
together with the fact that the "more swap space" case also degrades the
second time around seems to imply that we leave swap-cache pages around
after they aren't used.

Does "free" after a run has completed imply that there's still lots of
swap used? We _should_ have gotten rid of it at "free_swap_and_cache()"
time, but if we missed it..

What happens if you make the "vm_swap_full()" define in <linux/swap.h> be
unconditionally defined to "1"? That should make us be more aggressive
about freeing those swap-cache pages, and it would be interesting to see
if it also stabilizes your numbers.

		Linus