Messages in this thread | | | Date | Thu, 16 Aug 2001 21:26:38 -0400 | From | David Ford <> | Subject | Re: "VM watchdog"? [was Re: VM nuisance] |
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I think it is an excellent way to do it. Nobody said you have to run the program and nobody forces you to use a particular program with a particular policy. It puts the OOM policy in userland where -you- decide when and how things happen.
David
Jakob Østergaard wrote:
>>Maybe creating userland program that >>*) allocates few megs >>*) while 1 sleep 1m, gettimeofday. If more tha two minutes elapsed, >> tell OOM handler to kick in. >> > >On my compute-server in the basement this is completely unacceptable because it >*may* just be working hard on something big. The excessive swapping may just >be 10-30 minutes where some app is using way more memory than the box has RAM, >in this case it's no problem at all, and all your suggestion would give me is >randomly dying compute jobs. > >On my desktop this is unacceptable as well. You want the system to be frozen >for more than two minutes before doing anything about it ? > >The problem with using such vague heuristics against fixed (arbitrary) limits >is that the effect will almost always be completely unacceptable. Either your >arbitrary limit is way too high, or way too low. > >I can't tell you how to do it - but I think your suggestion is an excellent way >to *not* do it :) > >>Or maybe kernel could have some "VM watchdog", which would trigger OOM if >>it is not polled once a minute... >> > >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.
David
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