Messages in this thread | | | Date | Fri, 17 Mar 2000 13:21:34 +0000 (GMT) | From | James Sutherland <> | Subject | Re: Some questions about linux kernel. |
| |
On Fri, 17 Mar 2000, Rik van Riel wrote:
> On Thu, 16 Mar 2000, Paul Jakma wrote: > > On Thu, 16 Mar 2000, James Sutherland wrote: > > > > > No. *ANY* memory allocation system can run out of memory. Avoiding > > > "overcommitting" would make the OOM situation arise SOONER (and more > > > frequently), as well as killing performance. > > > > well, it's a more a question of whether you make promises that you > > might not be able to keep. If you do (ie overcommit) then it's your > > (kernel) problem. If you don't, it's not. > > > > So his processes STILL end up dying randomly, but they do it sooner rather > > > than later. Hrm. Wow. > > > > but then it's the users problem - not the OS.. > > Erhmm, sorry that I have to say this Paul, but this > sounds like non-overcommit is about shifting the blame > and not about fixing the problem...
In fact, it makes the problem worse.
> Knowing all of this, would you still want a non-overcommitting > system where you need more swap just to run out of memory sooner?
This is the core problem - it does not cause any improvement w.r.t. running out of memory. It does avoid some unrelated theoretical problem - but that's not the point here.
> If a renegade application steals all memory, it will cause > other (innocent) applications to die. Unless you have some > code in the kernel which is able to shoot down the renegade > process and save the rest.
Quite.
> (non-)overcommit isn't going to make any difference here...
I disagree with this bit - it will make the problem worse on any given configuration. For example, forking a load of Apache processes in 64Mb of RAM, no swap is fine with overcommit - but will cause OOM problems without overcommit. Certainly no improvement!
James.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |