Summary: 2> Which processes get killed off when you run out of swap?

From: <alan.garde_at_transport.uk.eds.com>
Date: Thu, 16 Sep 1999 08:47:35 +0100

I received this from Dr Blinn, which I will take as the definitive answer
for this!
If it was causing us a major problem I would get more disk... but currently
any new disks we
buy instantly get appropriated to stop those nasty users from filling up
/users...

Alan

---
When you are running swap overcommit mode, the process that dies usually
is a process that has not run in a long time, since it will have pages on
the "not used in a long time and eligible for recovery" list, and once a
page is on that list and selected by the memory management subsystem (we
call it the "virtual memory" system) to be swapped out and no swap space
is available, the process owning the page is killed (which resolves the
"page must be swapped out and no swap space is available" problem).  So,
the most likely process to die is one that has pages in memory that have
not been accessed in a long time.
If you can't manage the work load to prevent problems like this, then you
may need to run with "eager" swap and simply dedicate a whole lot of disk
space to swapping.  Yes, that's ugly.
Tom
 Dr. Thomas P. Blinn + UNIX Software Group + Compaq Computer Corporation
  110 Spit Brook Road, MS ZKO3-2/W17   Nashua, New Hampshire 03062-2698
   Technology Partnership Engineering           Phone:  (603) 884-0646
    Internet: tpb_at_zk3.dec.com           Digital's Easynet: alpha::tpb
     ACM Member: tpblinn_at_acm.org         PC_at_Home: tom_at_felines.mv.net
  Worry kills more people than work because more people worry than work.
      Keep your stick on the ice.        -- Steve Smith ("Red Green")
     My favorite palindrome is: Satan, oscillate my metallic sonatas.
                                         -- Phil Agre, pagre_at_ucsd.edu
     Yesterday it worked / Today it is not working / UNIX is like that
			-- apologies to Margaret Segall
  Opinions expressed herein are my own, and do not necessarily represent
  those of my employer or anyone else, living or dead, real or imagined.

Received on Thu Sep 16 1999 - 07:50:28 NZST