Re: 2.6.39-rc4+: Kernel leaking memory during FS scanning, regression?

["Bruno Prémont" <bonbons@linux-vserver.org>]

On Wed, 27 Apr 2011 15:07:17 "Paul E. McKenney" wrote:
> On Wed, Apr 27, 2011 at 10:40:23PM +0200, Bruno Prémont wrote:
> > On Wed, 27 April 2011 Bruno Prémont wrote:
> > > On Wed, 27 April 2011 Bruno Prémont wrote:
> > > > On Wed, 27 Apr 2011 00:28:37 +0200 (CEST) Thomas Gleixner wrote:
> > > > > Also please apply the patch below and check, whether the printk shows
> > > > > up in your dmesg.
> > > > 
> > > > > Index: linux-2.6-tip/kernel/sched_rt.c
> > > > > ===================================================================
> > > > > --- linux-2.6-tip.orig/kernel/sched_rt.c
> > > > > +++ linux-2.6-tip/kernel/sched_rt.c
> > > > > @@ -609,6 +609,7 @@ static int sched_rt_runtime_exceeded(str
> > > > >  
> > > > >  	if (rt_rq->rt_time > runtime) {
> > > > >  		rt_rq->rt_throttled = 1;
> > > > > +		printk_once(KERN_WARNING "sched: RT throttling activated\n");
> > > 
> > > This gun is triggering right before RCU-managed slabs start piling up as
> > > visible under slabtop so chances are it's at least a related!
> > 
> > Letting the machine idle (except running collectd and slabtop) scheduler
> > suddenly decided to restart giving rcu_kthread CPU cycles (after two hours
> > or so! if I read my statistics graphs correctly)
> 
> And this also returned the slab memory, right?

Exactly!

> Two hours is quite some time...
> 
> 							Thanx, Paul
> 
> > While looking at lkml during the above 2 hours I stumbled across this (the
> > patch of which doesn't help in my case) which looked possibly related.
> >   http://thread.gmane.org/gmane.linux.kernel/1129614
> > 
> > Bruno