Re: Slowmem support - turn uncacheable mem into ramdisk

Pavel Machek (pavel@elf.ucw.cz)
Tue, 10 Mar 1998 19:30:58 +0100


Hi!

> > This patch (relative to 2.1.89) helps systems with uncacheable (->
> > slow) memory. It adds one config time switch (sorry for strange
> > placement) and command line option.
>
> Very nice, but then we'd want to:
> - age buffer and cache pages
> - swap user pages on the first whim (when there's some
> fastswap left!)

I'm looking forward to see it.

> On a sidenote:
> Is it available from your homepage or should I add it to
> the mm-patch page?

Add it to mm-patch page. I'm currently ill, so I'm mostly online, only
reading / sending mail.

Question: While playing with mm subsystem, machine frequenly falls
into state where kswapd is active 99% of time, and machine is doing
anything usefull that remaining 1% of time. I'm sure I already saw this
behaviour on some older kernel. (May hacks are needed to do it on
2.1.89). I do not know how it is caused, but:

Pages' age must be 0 in order for page being swapped out. Ok, but what
if there are no pages with age 0? Should not page with lowest age
found be swapped out?

Pavel

-- 
I'm really pavel@atrey.karlin.mff.cuni.cz. 	   Pavel
Look at http://atrey.karlin.mff.cuni.cz/~pavel/ ;-).

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