Re: Subtle MM bug

[Zlatko Calusic <zlatko@iskon.hr>]

Simon Kirby <sim@stormix.com> writes:

> On Tue, Jan 09, 2001 at 10:47:57AM -0800, Linus Torvalds wrote:
> 
> > And this _is_ a downside, there's no question about it. There's the worry
> > about the potential loss of locality, but there's also the fact that you
> > effectively need a bigger swap partition with 2.4.x - never mind that
> > large portions of the allocations may never be used. You still need the
> > disk space for good VM behaviour.
> > 
> > There are always trade-offs, I think the 2.4.x tradeoff is a good one.
> 
> Hmm, perhaps you could clarify...
> 
> For boxes that rarely ever use swap with 2.2, will they now need more
> swap space on 2.4 to perform well, or just boxes which don't have enough
> RAM to handle everything nicely?
>

Just boxes that were already short on memory (swapped a lot) will need
more swap, empirically up to 4 times as much. If you already had
enough memory than things will stay almost the same for you.

But anyway, after some testing I've done recently I would now not
recommend anybody to have less than 2 x RAM size swap partition.

> I've always been tending to make swap partitions smaller lately, as it
> helps in the case where we have to wait for a runaway process to eat up
> all of the swap space before it gets killed.  Making the swap size
> smaller speeds up the time it takes for this to happen, albeit something
> which isn't supposed to happen anyway.
> 

Well, if you continue with that practice now you will be even more
successful in killing such processes, I would say. :)
-- 
Zlatko
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