mbuf clusters exhausted w/o reaching max?

[Bosko Milekic]

On Fri, Aug 01, 2003 at 03:28:35PM -0500, Mike Silbersack wrote:
> 
> On Fri, 1 Aug 2003, Steve Francis wrote:
> 
> > I have a FreeBSD 4.8-RELEASE #5 system that reported:
> > Aug  1 11:50:39 rack2-101 /kernel: All mbuf clusters exhausted, please see tuning(7).
> > Aug  1 11:50:39 rack2-101 /kernel: All mbufs exhausted, please see tuning(7).
> >
> > Yet its not close to the max allowed for clusters.
> > rack2-101.nyc# netstat -m
> > 1338/4240/131072 mbufs in use (current/peak/max):
> >         1338 mbufs allocated to data
> > 709/3366/32768 mbuf clusters in use (current/peak/max)
> > 7792 Kbytes allocated to network (7% of mb_map in use)
> > 50 requests for memory denied
> > 0 requests for memory delayed
> > 0 calls to protocol drain routines
> > rack2-101.nyc#
> 
> Mbufs & mbuf clusters are allocated from the kernel map, so it's possible
> for allocations to fail due to the kernel map being relatively full due to
> other parts of the kernel eating memory.  This is probably what's
> happening in your case; given that only 50 allocations were denied, it
> probably didn't hurt your system much.

  Actually, he's not running out of address space here; he's probably
  run out of free pages and could not block to wait for them.

-- 
Bosko Milekic  *  bmilekic at technokratis.com  *  bmilekic at FreeBSD.org
TECHNOkRATIS Consulting Services  *  http://www.technokratis.com/