Re: "VM watchdog"? [was Re: VM nuisance]

[klink@clouddancer.com (Colonel)]

In clouddancer.list.kernel, David wrote:

>>Didn't everyone pretty much agree that if we could turn off overcommit
>>completely and reliably, that would be the preferred solution ?   Simply sig11
>>the app that's unlucky enough to want more memory than there's in the system
>>(or, horror, have malloc() fail)
>>
>>Now, I don't remember the entire thread, but IIRC it was difficult to kill
>>overcommit completely.
>>
>
>The kernel allocates memory within itself.  We will still reach OOM 
>conditions.  It can't be avoided.

That doesn't sound good.

What bugs me about this statement was that until 2.4, I never had
lockups.  I sometimes had a LOT of swapping and slow response, but I
also knew that running a complex numeric simulation when RAM <
'program needs' does that.  I accepted it and tended to arrange such
runs in my absence.  Now I find that I get some process nuked (or
worse - partially nuked) even after increasing to 4x swap and
eliminating lazy habits that would leave some idle process up for a
few days in case I needed it again (worked fine in 2.0.36).  There are
_alot_ of good things in 2.4, but sometimes....


Does your statement imply that a machine left "alone" must eventually
OOM given enough runtime??  It seems that it must.


-- 
2.4 VM: "I'm sorry Dave ...  I'm afraid I can't do that."