Re: Running out of memory in 4.0?

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Dec 01, 2008 at 05:33:02PM +0100, Havard Eidnes wrote:
> Hi,
> 
> we have a system which runs as a Xen domU where we have been
> experiencing a lack of stability.  It will appear to hang with
> irregular frequency.  The domU uses NFS for all its I/O, including
> swap.
> 
> We have had two separate types of symptoms, which probably both
> have the same underlying cause.
> 
> In the first instance, the kernel would sometimes grind to a halt
> endlessly spewing these messages on the console:
> 
>    xennet: rx no mbuf
>    xennet: rx no mbuf
>    xennet: rx no mbuf
> 
> One of the times it did this, I managed to get into DDB, and,
> yes, indeed, it had run completely out of free pages, according
> to the "show uvmexp" output ("0 free" in the "show uvm" output).
>[...] 

Looks a lot like kern/40027. I've seen it mostly on netbsd-5 and -current,
but a 4.0 domU managed to exibit this symptoms too (it has swap on
xbd, not on NFS though). As in my case, there is still some
memory that could be reclaimed from the pagedaemon, but it fails
to do so, and seems to be in a loop ...

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--