Subject: Re: Swapping and diskless systems
To: Charles M. Hannum <mycroft@mit.edu>
From: Stefan Grefen <grefen@hprc.tandem.com>
List: tech-kern
Date: 09/08/1998 19:40:06
In message <199809080940.FAA01854@lunacity.ne.mediaone.net>  "Charles M. Hannum" wrote:
> 
> So I noticed a serious -- and somewhat funny -- problem with nfsiod
> and diskless systems yesterday.  We allow the u-area of the nfsiod
> process to be swapped out.
> 
> This is a problem for two reasons:
> 
> 1) In the best case, it means that in a low memory situation NFS
>    performance will be severly hosed as we spend a bunch of time
>    paging in and out u-areas to free up memory.
> 
> 2) In the worst case, it will result in a deadlock.  (Can you say
>    `swapping out the swapper'?)
> 
> Oops.

Why not mlock it?? I would consider a it a serious bug if process with
locked pages can be swapped.

Stefan

--
Stefan Grefen                                Tandem Computers Europe Inc.
grefen@hprc.tandem.com                       High Performance Research Center
 --- Hacking's just another word for nothing left to kludge. ---