kernel panic, zone kalloc.8192 exhaustion

[Marcus Brinkmann]

Hi,

with the proc bug fix, the Hurd core is very stable.  In fact, I had an
uptime of 16 hours, and handled over 100000 processes over all.

Then it crashed with

panic: zalloc: zone kalloc.8192 exhausted

The question that arises is, if there is some sort of leak (and which type
of leak could this be), or if the zone limits are simply too small for
todays machine.  Maybe even both is true.  The reason why I find a leak is
possible is that I was not adding a lot of load at the time I got the panic,
but maybe it is also some other, more subtle problem.

I have almost no feeling for how much is allocated in these zones and what
objects come where, and if the number of objects remains small and more or
less constant under the same load, or if they can queue up etc...  maybe we
will only find out with some serious tracing/debugging.

The current zone limits are below (from kern/kalloc.c).  The reason the 8192
zone is so large is that many messages fall into it.  Maybe there were just
to many extant messages (thanks, Neal).

unsigned long k_zone_max[16] = {
      1024,             /*      1 Byte  */
      1024,             /*      2 Byte  */
      1024,             /*      4 Byte  */
      1024,             /*      8 Byte  */
      1024,             /*     16 Byte  */
      4096,             /*     32 Byte  */
      4096,             /*     64 Byte  */
      4096,             /*    128 Byte  */
      4096,             /*    256 Byte  */
      1024,             /*    512 Byte  */
      1024,             /*   1024 Byte  */
      1024,             /*   2048 Byte  */
      1024,             /*   4096 Byte  */
      4096,             /*   8192 Byte  */
      64,               /*  16384 Byte  */
      64,               /*  32768 Byte  */
};

Marcus

-- 
`Rhubarb is no Egyptian god.' Debian http://www.debian.org brinkmd@debian.org
Marcus Brinkmann              GNU    http://www.gnu.org    marcus@gnu.org
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de