4.8-STABLE Kernel Panic with dummynet options.

[Dmitry Pryanishnikov]

Hello!

On Wed, 9 Apr 2003 15:13:53 +0400, Sergey A. Osokin wrote:
>> options    NMBCLUSTERS=1024
>> options    NMBUFS=4096
>
> What is the NMBUFS? You talk about NSFBUFS?

 Nope, there is NMBUFS - number of single mbufs vs NMBCLUSTERS for
mbuf clusters. You can see current usage:

root at atlantis# netstat -m
1080/2736/32768 mbufs in use (current/peak/max):
        1010 mbufs allocated to data
        70 mbufs allocated to packet headers
781/2434/16384 mbuf clusters in use (current/peak/max)

(1st line for mbufs, 4th for mbuf clusters) and adjust both values in
/boot/loader.conf:

kern.ipc.nmbufs="32768"         # Number of mbufs
kern.ipc.nmbclusters="16384"    # Number of mbuf clusters

Note the following sanity check in kernel:

        /* Sanity checks */
        if (nmbufs < nmbclusters * 2)
                nmbufs = nmbclusters * 2;

> AFAIK 1024 is very-very small value for NMBCLUSTERS.

 Well, it depends ;) Really, one of my routers shows the following:

dmitry at cs37$ netstat -m
69/560/6144 mbufs in use (current/peak/max):
        69 mbufs allocated to data
35/206/1536 mbuf clusters in use (current/peak/max)

after uptime of 46 days (total traffic up to several Mbit/s, 6 network
interfaces, dummynet in use).

On Wed, 9 Apr 2003 16:00:46 +0400, Sergey A. Osokin wrote:
>> And what about the HZ value?
>
> AFAIK its compile time option.

 It's also boot-time tunable long time ago, see 4.4-RELEASE release notes:

   The maxusers kernel configuration parameter is now a boot-time tunable
   variable. The kernel parameters derived from maxusers are now also
   tunables and can be overridden at boot-time. The hz parameter is also now
                                                    ^^^^^^^^^^^^
   a tunable.

 So one can just set HZ to some reasonable value (200, 500, 1000 - it depends
also) in loader.conf:

kern.hz="200"                   # Clock interrupts per second


Sincerely, Dmitry
-- 
Atlantis ISP, System Administrator
e-mail:  dmitry at atlantis.dp.ua
nic-hdl: LYNX-RIPE