Re: Dom0 xvif mbuf issues

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

On Mon, Oct 01, 2018 at 05:10:19PM -0700, Harry Waddell wrote:
> > Looks like temporary memory shortage in the dom0 (this is a MGETHDR failing,
> > not MCLGET, so the nmbclusters limit is not relevant).
> > How many mbufs were allocated ?
> > 
> At the time of the hang, I have no idea. 
> 
> It's around 512 whenever I check. 
> 
> [root@xen-09:conf]> netstat -m
> 515 mbufs in use:
> 	513 mbufs allocated to data
> 	2 mbufs allocated to packet headers
> 0 calls to protocol drain routines

Looks like the receive buffers for the ethernet interface.

> > > It hung again, but with a new 
> > > error scrolling on the console. "xennetback: got only 63 new mcl pages"  
> > 
> > This would point to a memory shortage in the hypervisor itself.
> > Do you have enough free memory (xl info) ?
> > 
> total_memory           : 131037
> free_memory            : 26601
> sharing_freed_memory   : 0
> sharing_used_memory    : 0
> outstanding_claims     : 0

that should be plenty. No idea why xennetback couldn't get the 64 pages
it asked.

> > > This is a production system with about 30 guests. I just want it to work like it used to.   
> > 
> > how many vifs is there in the dom0 ?
> > 
> 
> I expect this is not an ideal way to do this but ...
> 
> (for i in `xl list | awk '{print $1}'`;do xl network-list $i | grep vif ;done) | wc -l
>       57
> 
> Several of the systems are part of a cluster where hosts are multihomed on 2 of 4 networks
> to test a customer setup. Most of my systems have < 30, except for one other with 42. 
> The others don't hang like this one does. 

I have more than 100 here.

Maybe you should try reverting
kern.sbmax=1048576                   
net.inet.tcp.recvbuf_max=1048576     
net.inet.tcp.sendbuf_max=1048576     

to their default values.

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