Subject: Re: Swap overcommit (was Re: Replacement for grep(1) (part 2))
To: Charles M. Hannum <>
From: David Greenman <>
List: tech-userlevel
Date: 07/13/1999 19:25:10
>The point is, the OS should have provided *some* mechanism to insure
>that the long-running process wasn't affected.  It didn't.  That's a
>clear failure of the OS to provide a reasonable environment for this
>type of computing.
>Whether this should be solved by switching to a no-overcommit policy,
>fiddling with the overcommit policy in some way, or whatever, is a
>different issue.  But you have not yet proposed any mechanism that
>would have prevented this problem while still permitting me to get
>work done.

   I've long felt that the best solution to problems like this is a per-user
swap space quota. This gives admins a knob to manage the allocation of swap
space while still allowing overcommit. The downside is that it doesn't provide
a graceful way for a program to recover from it's overconsumption sins. I'd
argue, however, that buggy software or incorrectly tuned systems should get
what they deserve.


David Greenman
Co-founder/Principal Architect, The FreeBSD Project -
Creator of high-performance Internet servers -