On Fri, 23 Mar 2001, Guest section DW wrote:

quoted

On Thu, Mar 22, 2001 at 10:52:09PM +0000, Alan Cox wrote:

quoted

You can do overcommit avoidance in Linux if you are bored enough to try it.

Would you accept it as the default? Would Linus?

It wouldn't help.  Suppose you run without overcommit and you
fill up RAM and swap to the last page.

Then you change the size of one of the windows on your desktop
and a program gets sent -SIGWINCH.

 Ignoring the fact that most people don't use a tty based desktop, and
that I'm pretty happy having my desktop die in flames when OOM (my DNS
or smtp server on the other hand...).

                                   In order to process this
signal, the program needs to allocate some variables on its
stack, possibly needing a new page to be allocated for its
stack ...

man sigaltstack

... and since this is something which could happen to any program
on the system, the result of non-overcommit would be getting a
random process killed (though not completely random, syslogd and
klogd would get killed more often than the others).

 I fail to see why, stack usage can be limited (and possibly cleanly
handled by having a prctl() to say make sure X pages are available on
the stack).

 If you want overcommit great, and I think it's a valid default
... but it'd be nice if I could say I don't want it for apps that
aren't written using glib etc.

-- 
# James Antill -- james@and.org
:0:
* ^From: .*james@and\.org
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