Re: [RCU problem] was VFS: file-max limit 50044 reached

[Dipankar Sarma <dipankar@in.ibm.com>]

On Mon, Oct 17, 2005 at 02:10:09PM +0200, Eric Dumazet wrote:
> Dipankar Sarma a écrit :
> >On Mon, Oct 17, 2005 at 11:10:04AM +0200, Eric Dumazet wrote:
> >
> >Agreed. It is not designed to work that way, so there must be
> >a bug somewhere and I am trying to track it down. It could very well
> >be that at maxbatch=10 we are just queueing at a rate far too high
> >compared to processing.
> >
> 
> I can freeze my test machine with a program that 'only' use dentries, no 
> files.
> 
> No message, no panic, but machine becomes totally unresponsive after few 
> seconds.
> 
> Just greping for call_rcu in kernel sources gave me another call_rcu() use 
> from syscalls. And yes 2.6.13 has the same problem.

Can you try it with rcupdate.maxbatch set to 10000 in boot
command line ?

FWIW, the open/close test problem goes away if I set maxbatch to
10000. I had introduced this limit some time ago to curtail
the effect long running softirq handlers have on scheduling
latencies, which now conflicts with OOM avoidance requirements.

Thanks
Dipankar