Subject: Re: userid partitioned swap spaces: note that running out of swap no longer crashes the machine.
To: Jukka Marin <jmarin@pyy.jmp.fi>
From: Ignatios Souvatzis <ignatios@theory.cs.uni-bonn.de>
List: tech-kern
Date: 12/18/1998 11:35:24
On Fri, Dec 18, 1998 at 12:30:18PM +0200, Jukka Marin wrote:
> On Fri, Dec 18, 1998 at 11:25:17AM +0100, Ignatios Souvatzis wrote:
> > I started to read Charles Cranors thesis about the UVM virtual memory system
> > now integrated in NetBSD (after the 1.3 release), and he states that UVM, 
> > unlike the old Mach VM used earlier, detects running out of swap and sends 
> > an error signal to a process if it tries to access a page for which anonymous
> > backing store would be needed, but isn't (currently) available. (SIGSEGV, I
> > guess).
> 
> This still won't help if the unlucky process happens to be inetd or named
> or something essential.. but the other solutions (allowing only root
> processes to allocate swap after a certain point) would help.

Hm, if it makes sure to touch every page it needs on start-up, it will be
safe later. ;-)

	-is