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. ---