Re: Out of memory, but no OOM Killer? (2.6.9-ac11)

[Ralf Hildebrandt]

* Nick Piggin <nickpiggin@xxxxxxxxxxxx>:

> >I see. rsync requested a big chunk of memory, but failed due to the
> >fragmentation of free memory? my "sar" output shows lots of free memory and
> >lots of unused swap:
> >
> 
> Basically, yes. Well not *exactly* rsync - your network drivers. I guess
> rsync is showing up in process context most often because that is the
> process causing most of the network activity.

At that time, yes.

> Yep, it looks like fragmentation is indeed the problem here. See you have
> a lot of memory that is able to be reclaimed, but the failing allocations
> themselves can't reclaim any of it because they are happening from
> interrupts. What they should be doing is telling `kswapd` to start freeing
> memory for them - however this currently doesn't happen properly for
> allocations which are order greater than 0.
> 
> Fortunately that is usually not a big problem, but as you have seen, it
> can be. Anyway, expect 2.6.10 to be better (ie. good enough), and 2.6.11
> should have even more complete fixes.

Aha.

> OK that should be fine. If you should upgrade to a 2.6.10 or later kernel,
> put this value back to the default, and report further problems if they
> occur.

I just set it "for now"

-- 
Ralf Hildebrandt (i.A. des IT-Zentrum)          Ralf.Hildebrandt@xxxxxxxxxx
Charite - Universitätsmedizin Berlin            Tel.  +49 (0)30-450 570-155
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