Re: ~500 megs cached yet 2.6.5 goes into swap hell

Hugh Dickins
2004-05-17T20:16:44Z

On Wed, 12 May 2004, Rob Landley wrote:
> On Friday 07 May 2004 11:57, Pavel Machek wrote:
> > Hi!
> >
> > > > Perhaps what we really want is "swap_back_in" script? That way you
> > > > could do "updatedb; swap_back_in" in cron and be happy.
> > >
> > > swapoff -a; swapon -a
> >
> > Good point... it will not bring back executable pages, through.
> >
> > Pavel
>
> What would the above do if there wasn't enough memory to swap everything back
> in? (Presumably, the swapoff would fail?)

Repeating my earlier reply to a similar question...

On 2.4 it certainly would be a problem (hang with others OOM-killed).

On 2.6 it shouldn't be a problem: the swapoff may fail upfront if
there's way too little memory, or it may get itself OOM-killed if
it runs out on the way, but it ought not to upset other tasks.

But of course, Pavel is right that it does nothing for file backed.

Hugh