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RE: dst cache overflow 2.2.x; x>=16

To: <netdev@xxxxxxxxxxx>, "Julian Anastasov <ja@xxxxxx>" <IMCEANOTES-+22Julian+20Anastasov+20+3Cja+40ssi+2Ebg+3E+22@xxxxxxxxxxxxxxx>
Subject: RE: dst cache overflow 2.2.x; x>=16
From: "Milam, Chad" <Chad_Milam@xxxxxxxxxx>
Date: Mon, 15 Apr 2002 15:58:11 -0400
Sender: owner-netdev@xxxxxxxxxxx
Thread-index: AcHkttOs5RbXq7bUQBG74Lh9ie+HnAAAFZQQ
Thread-topic: RE: dst cache overflow 2.2.x; x>=16
Julian wrote:
> On Mon, 15 Apr 2002, Milam, Chad wrote:
> 
> > > can only give you some CPU cycles. Touching max_size should be
> > > enough.
> >
> > no. Increasing max_size only delays its death. That is my point. The problem
> > existed on an out of the box RH7, RH6.2, RH6.1 install. The whole point of 
> > the
> > patch was to fix a problem that existed _prior_ to me patching it.
> 
>       I assume you mean a plain kernel (without Check Point?).

indeed.. out of the box, nothing installed additional, ip params tuned.

> 
> > >   Are you sure you have stalled entries? What shows /proc/slabinfo
> > > after 22 hours (skbuff_head_cache, etc)?
> >
> > well, what I can tell you is this. If I run a loop like the following, 
> > counter
> > will only show say, 50 routes in the cache.
> 
>       It means there are 50 linked cache entries but the
> ipv4_dst_ops.entries reaches the limit, very strange.

this is what I am keep trying to say :)

 
> > > for i in down up ; do ip link set ethXXX $i ; done
> >
> > downing all interfaces and reupping them does not seem to solve the problem 
> > either :S
> 
>       I mean when you see the dst cache overflow message can the
> command help? But ... may be are running a kernel patched with your
> changes. I'm asking this because I know cases where wrong changes
> can make problems with dst cache. But the plain kernel should be
> fine. One question more: can you say that this box is used only as
> router or what kind of TCP or UDP connections you have (to/from the
> box)? There can be some corner cases in the dst cache usage from
> connected sockets.

I originally setup a script to do basically this... grep "dst cache" 
/var/log/messages; if i get a hit, down and up all interfaces.  that didnt
work, so then I changed it to reboot the box :(.  This was done on a box
with _no_ funny stuff... again, bog standard.

The box is a router, no ip masq, no ip chains, no ip fw, just a router.

Thanks,
chad



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