[ILUG] Out of Memory

[John P. Looney]

On Mon, Mar 06, 2000 at 12:22:06PM +0000, Paul Jakma mentioned:
> but how /do/ you handle OOM? you are totally out of memory, you can't
> swap out processes cause swap is full, the kernel can't allocate memory
> for net packets that are too big for static buffers..

 When a process malloc's memory, you return a null pointer, and the
program should quit (if it's well written) or soon core dump, if it's
not. The kernel should reserve the last meg or two for itself, so it could
keep running until enough processes are given the chop.

> everyone says but OOM doesn't happen to OS xyz, and they might be right,
> but how these other OS's do it? do these OS's need lot's of swap for
> example? Are these other os's perhaps very very anal about memory? And
> are these other OS's perhaps a lot slower than linux?

 They do it different ways. But they all work. And believe me, a Solaris
machine with five MB free is about a million times faster than a Linux
box. I've seen netscape memory leak over a weekend until it used up all
RAM. It took me twenty five minutes to kill it, the machine was so slow at
swapping. And it was doing nothing bar running a bloated netscape. Granted
it was running 2.2.0, but still.

Kate

-- 
"The fool must be beaten with a stick, for an intelligent person 
the merest hint is sufficient"                -- Zen Master Greg