Re: Kswapd flaw

[Helge Hafting <helgehaf@aitel.hist.no>]

On Tue, Jun 28, 2005 at 02:47:15PM +0300, Al Boldi wrote:
> On 28 Jun 2005, Al Boldi murmured woefully:
> > Kswapd starts evicting processes to fullfil a malloc, when it should 
> > just deny it because there is no swap.
> Nix wrote:
> > I can't even tell what you're expecting. Surely not that no pages are ever
> evicted or flushed;
> > your memory would fill up with page cache in no time.
> 
> Nix,
> Please do flush anytime, and do it in sync during OOMs; but don't evict
> procs especially not RUNNING procs, that is overkill.

Something running rarely gets thrown out - It is usually only pages
that see little use that gets evicted.  Such as startup code.

Of course you can improve the situation a lot by adding swap - the kernel
will then be free to swap out dirty but little-used pages instead
of not-dirty but more used executable mappings. That will improve
your performance.

Getting more memory or running fewer programs also helps, obviously.

Helge Hafting