Subject: Re: Replacement for grep(1) (part 2)
To: David Malone <>
From: Brian Stark <>
List: tech-userlevel
Date: 07/13/1999 14:34:45
On Tue, 13 Jul 1999, David Malone wrote:

> I think AIX sends all running processes a magic signal (SIGDANGER?)
> which indicates that the system is short of resources, and if things
> don't improve real soon then it sends a SIGKILL. Not that I'd suggest
> that AIX does things the right way...

FYI, from InfoExplorer on an AIX 4.2.1 server:

"The system monitors the number of free paging space blocks and detects
when a paging-space shortage exists. When the number of free paging-space
blocks falls below a threshold known as the paging-space warning level,
the system informs all processes (except kprocs) of this condition by
sending the SIGDANGER signal. If the shortage continues and falls below a
second threshold known as the paging-space kill level, the system sends
the SIGKILL signal to processes that are the major users of paging space
and that do not have a signal handler for the SIGDANGER signal (the
default action for the SIGDANGER signal is to ignore the signal). The
system continues sending SIGKILL signals until the number of free
paging-space blocks is above the paging-space kill level."



| Brian Stark                       | Internet : |
| Siemens PT&D, LLC                 | Voice    : +1 612 536-4697        |
| Power Systems Control Division    | Fax      : +1 612 536-4919        |
| 7225 Northland Drive, Brooklyn Park, Minnesota 55428   USA            |