Re: Break 2.4 VM in five easy steps

Sean Hunter (sean@dev.sportingbet.com)
Wed, 6 Jun 2001 09:54:31 +0100


On Wed, Jun 06, 2001 at 10:19:30AM +0200, Xavier Bestel wrote:
> On 05 Jun 2001 23:19:08 -0400, Derek Glidden wrote:
> > On Wed, Jun 06, 2001 at 12:16:30PM +1000, Andrew Morton wrote:
> > > "Jeffrey W. Baker" wrote:
> > > >
> > > > Because the 2.4 VM is so broken, and
> > > > because my machines are frequently deeply swapped,
> > >
> > > The swapoff algorithms in 2.2 and 2.4 are basically identical.
> > > The problem *appears* worse in 2.4 because it uses lots
> > > more swap.
> >
> > I disagree with the terminology you're using. It *is* worse in 2.4,
> > period. If it only *appears* worse, then if I encounter a situation
> > where a 2.2 box has utilized as much swap as a 2.4 box, I should see the
> > same results. Yet this happens not to be the case.
>
> Did you try to put twice as much swap as you have RAM ? (e.g. add a 512M
> swapfile to your box)
> This is what Linus recommended for 2.4 (swap = 2 * RAM), saying that
> anything less won't do any good: 2.4 overallocates swap even if it
> doesn't use it all. So in your case you just have enough swap to map
> your RAM, and nothing to really swap your apps.
>

For large memory boxes, this is ridiculous. Should I have 8GB of swap?

Sean
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