Subject: Re: Swap overcommit (was Re: Replacement for grep(1) (part 2))
To: John Nemeth <>
From: Daniel C. Sobral <>
List: tech-userlevel
Date: 07/15/1999 12:36:34
John Nemeth wrote:
> } > But that isn't always the best process to have killed off...
> }
> } Sure it is. :-) Let's see...
>      This statement is absurd.  Only a comptetant admin can decide
> which process can be killed.  No arbitrary decision is going to be
> correct.

We are talking about what process the OS should kill automatically
when it reaches this situation. What is the criteria that should be
used? Is the "biggest process" the "best" process to be killed? Or
is there another, better criteria?

In this context, the statement makes perfect sense, even if you
disagree with it.

> } interesting, and a good implementation will very probably be
> } committed. *BUT*, this is not as useful as it seems. Since the
> } correct solution is buy more memory/increase swap (correct solution
> } for our target markets, anyway), there is little incentive to
> } implement it.
>      In case you hadn't noticed, this debate is cross-posted to
> NetBSD.  NetBSD's target market isn't the same as FreeBSD's target
> market.  This answer is NOT the correct solution for NetBSD's target
> market.  Heck, except for one rather vocal person, FreeBSD's target
> market may not consider it to be the correct solution either.  I most
> certainly do not consider it to be correct, and I admin a lot of
> mission critical servers.

I noticed, but I do not speak for NetBSD. Well, I do not speak for
FreeBSD either, but I have well informed opinions on it. What I say,
I say about FreeBSD.

As for being "correct", it's really simple. Either you have enough
memory, or you do not. If you don't have enough memory, a number of
programs cannot function correctly. Sure, some programs might be
able to deal with low-memory situations, but *other* programs
*cannot* deal with it. It's impossible for them to accomplish their
tasks if there is not enough memory. So, if you want that server to
accomplish it's job, you need more memory.

Which, btw, is cheaper than the man-hours needed to implement

Daniel C. Sobral			(8-DCS)

	"Would you like to go out with me?"
	"I'd love to."
	"Oh, well, n... err... would you?... ahh... huh... what do I do