Re: New patch (was Re: [PATCH] swapin readahead v3 + kswapd fixes)

[Linus Torvalds <torvalds@transmeta.com>]

On Mon, 21 Dec 1998, Stephen C. Tweedie wrote:
> 
> pre2 works OK on low memory for me but its performance on 64MB sucks
> here.  pre3 works fine on 64MB but its performance on 8MB sucks even
> more.

I'm testing it now - the problem is probably just due to my mixing up the
pre-2 and pre-3 patches, and pre-3 got the "timid" memory freeing
parameters even though the whole point of the pre-3 approach is that it
isn't needed any more.

>	  You simply CANNOT tell from looking at the code that it "will
> work well for everybody out there on every hardware".  

Agreed.

However, I very much believe that tweaking comes _after_ the basic
arhictecture is right. Before the basic architecture is correct, any
tweaking is useful only to (a) try to make do with a bad setup and (b) 
give hints as to what makes a difference, and what the basic architecture
_should_ be. 

As such, your "current != kswapd" tweak gave a whopping good hint about
what the architecture _should_ be. And we'll be zeroing in on something
that has both the performance and the architecture right. 

		Linus

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