Re: User space out of memory approach

Ilias Biris
2005-01-11T20:46:16Z

well looking into Alan's email again I think I answered thinking on
the wrong side :-) that the suggestion was to switch off OOM
altogether and be done with all the discussion... tsk tsk tsk too
defensive and hasty I guess :-)

Thinking it in another way alan's email could have the dimension of
switching off overcommitment (and thus OOM) whilst in the user-space
ranking stage to avoid reentrancy and invocation of oom again and
again before killing something. It also solves the issue of using
timed/counted resources which is plain ugly and evil. It would though
be necessary to switch OOM back on when the OOMK has finally done the
kill.

Did I get it right this time Alan?

On Tue, 11 Jan 2005 15:16:04 -0400, Ilias Biris <xyz.biris@gmail.com> wrote:
> Hi
>
> where I come from we say (jokingly of course) 'got a headache? chop
> your own head ... end of problem'.
>
> Though your system is not guaranteed to become more stable. When you
> forbid overcommitting memory, all you do is make failure occur for ALL
> processes at a different time. A process is happily doing something
> useful when all of a sudden its fork may die due to 'out of memory'
> ... Moreover shutting down overcommit will do that for all processes,
> not just the one culprit that could be chopped off by oom...
>
> Maybe it is just me but I think with overcommiting a system works more
> reliably :-)
>
> On Tue, 11 Jan 2005 16:32:23 +0000, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > On Maw, 2005-01-11 at 08:44, Thomas Gleixner wrote:
> > > I consider the invocation of out_of_memory in the first place. This is
> > > the real root of the problems. The ranking is a different playground.
> > > Your solution does not solve
> > > - invocation madness
> > > - reentrancy protection
> > > - the ugly mess of timers, counters... in out_of_memory, which aren't
> > > neccecary at all
> > >
> > > This must be solved first in a proper way, before we talk about ranking.
> >
> > echo "2" >/proc/sys/vm/overcommit_memory
> >
> > End of problem (except for extreme cases) and with current 2.6.10-bk
> > (and -ac because I pulled the patch back into -ac) also for most extreme
> > cases as Andries pre-reserves the stack address spaces.
> >
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>
>
> --
> Ilias Biris
>

--
Ilias Biris