[H-GEN] out of memory?!

[Greg Black]

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Sandra Milne wrote:

| I just had 4 ssh sessions to my gateway killed (not all at once, in a row). 
| I hooked up a monitor and found that there was only 6 meg of memory free!!!

How do you know?  (This is a serious question -- it's very
difficult to interpret "free memory" data provided by Unix
systems, and I expect this is true of Unix-like systems.)

The box I'm writing this on claims to have only 1M of memory
free at this minute, out of the 384M of real memory that it has.
But it has only ever used 10M out of its 1G of swap in the 157
days that it has been running.  If I start another 20 processes
right now (on top of the 241 that are running), they will all
start instantly and won't have the slightest idea that memory is
tight.  That's because there is in fact no shortage of memory on
this box.

| I'm pretty sure I know what the cause of the problem is (gdm keeps crashing 
| and respawning) but is there a way to clear memory without rebooting?

Except on seriously broken systems, a process's memory is freed
when the process exits.  You cannot get it back before the
process dies; you definitely get it back when the process dies.

If gdm cannot run reliably, you'd be best to try a better
program (xdm comes to mind).  And I'm surprised that you'd want
to run either of those on a gateway ...

Greg

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