Running with vm.overcommit_memory=2

[Ralf Ertzinger <fedora-devel camperquake de>]

Hi.

After having firefox killed by the OOM-killer due to a totem running wild
(and watching the killer churn the disks for 5 minutes to do so, what the heck
is it doing?), I ventured to try a hard overcommit limit (which setting
vm.overcommit_memory=2 does, to the best of my knowledge). The system in
question has 640MB RAM, no swap.

The result is that almost nothing works, even with plenty of memory free.
It's even impossible to get a simple man page to display:

[sun nausicaa ~/src/gmemusage-0.2 :) 23]$ free
             total       used       free     shared    buffers     cached
Mem:        645152     366636     278516          0      16900     106340
-/+ buffers/cache:     243396     401756
Swap:            0          0          0
[sun nausicaa ~/src/gmemusage-0.2 :) 24]$ man sysctl
sh: fork: Cannot allocate memory
sh: fork: Cannot allocate memory
Error executing formatting or display command.
System command (cd /usr/share/man && (echo ".ll 11.8i"; echo ".pl 1100i"; /usr/bin/gunzip -c '/usr/share/man/man8/sysctl.8.gz'; echo ".\\\""; echo ".pl \n(nlu+10") | /usr/bin/gtbl | nroff --legacy ISO-8859-1 -man -rLL=129n -rLT=129n 2>/dev/null | /usr/bin/less -iRs) exited with status 32768.
No manual entry for sysctl

The system has nearly 400MB of free memory. What does it take to display
some lines of text these days?

-- 
"It's one of those irregular verbs: I explore the possibilities of
computing, you hack, he has been charged under section 2 of the computer
misuse act..."  -- Richard Watts