Re: [PATCH 0/3] NFS regression in 2.6.26?, "task blocked for more than 120 seconds"

Kasparek Tomas
2009-01-18T13:08:40Z

On Fri, Jan 16, 2009 at 11:48:02AM +0100, Kasparek Tomas wrote:
> On Tue, Jan 13, 2009 at 04:22:01PM +0100, Kasparek Tomas wrote:
> > On Mon, Jan 12, 2009 at 08:17:26PM -0500, Trond Myklebust wrote:
> > > On Mon, 2009-01-12 at 12:40 -0500, Trond Myklebust wrote:
> > > > On Mon, 2009-01-12 at 10:04 +0100, Kasparek Tomas wrote:
> > > > > Ok, I find that allready. With static mount the behaviour is the same as
> > > > > with amd - no new connection is created and the client waits forever (~
> > > > > tens of hours at least).
> > > >
> > > > OK. I now appear to be able to reproduce this problem. I should have a
> > > > fix ready soon.
> > >
> > > The attached 2 patches have been tested using a server that was rigged
> > > not to ever close the socket. They appear to work fine on my setup,
> > > without the hang that you reported earlier.
> >
> > after 8hours it seems it works both with static mount and with amd. I will
> > let you know the state after few more days again.
> >
> > Thank you very much for your help.
>
> Just confirming, that the last patch did help and it works well both with
> static mount and amd.
>
> Thank you very much for repairing this. Should I do something more, or can
> you propagate the change into vanilla and if possible to Greg for stable to
> get into 2.6.27.x ?

Hi Trond, for now please do not push your patches to mainstream, I have some
big troubles with my machines and it starts loking like the new kernel may
be the cause.

It seems that machines with this new kernel (tried on 10 other machines
and the original client) may after few days get into state where they
generate huge amounts (10000-100000pkt/s) of packets on another server they
use (Linux 2.6.26.62, but the same behaviour with other kernels I tried -
2.6.24.7, 2.6.22.19, 2.6.27.10). It seems packets are quiet small as the
flow on server is about 5-10MB/s. (probably) Each packet generates an answer.
With this flow it is hard to get more info and the server is production
one, so for now I only know it goes from these clients and end on tcp port
2049 on that server. It kills just this server, communication with the
previously problematic (FreeBSD machines) is fine now.

Will try to investigate more details.

Thanks.

--

Tomas Kasparek, PhD student E-mail: kasparek@fit.vutbr.cz
CVT FIT VUT Brno, L127 Web: http://www.fit.vutbr.cz/~kasparek
Bozetechova 1, 612 66 Fax: +420 54114-1270
Brno, Czech Republic Phone: +420 54114-1220

jabber: tomas.kasparek@jabber.cz
GPG: 2F1E 1AAF FD3B CFA3 1537 63BD DCBE 18FF A035 53BC