topic Tru64 5.1 kernel memory management. in Operating System - Tru64 Unix

Tru64 5.1 kernel memory management.

Darren Reed — Tue, 11 May 2004 15:14:23 GMT

Hi,
That prior messages was a mistake...

I'm having issues with the kernel memory allocator in Tru64 5.1 and IPFilter.

On a 96MB AlphaSTATION 433, I can load IPFilter without any problems. The exact same code compiled fails to load on a 256MB pc164 bsaed computer because of a 16k kernel memory bucket allocation failure.

The relevant line of output from "vmstat -M" is:
bkt elem_sz in_use el_free bytes fail_nowait
10 16384 3 4 49152 21

I've not tried to tune any kernel parameters, this is just the default setup.

Does anyone know what I need to do to fix this?

Re: Tru64 5.1 kernel memory management.

Ralf Puchner — Tue, 11 May 2004 17:59:47 GMT

please don't interpret message, post it in original context. Is your message "vmunix: malloc failed: bucket size"?

If so the root cause of the problem could be: memory leak or wrong kernel parameters leading to an allocation problem.

For a starter use sys_check and correct the parameters marked within the output.

Re: Tru64 5.1 kernel memory management.

Hein van den Heuvel — Wed, 12 May 2004 00:13:56 GMT

I'm with Ralf on this. Please start out with the exact (console?) message. Help us understand what made you worry about the 'kernel memory allocator'.

Good call on the: vmstat -M,
but maybe you over-reduced the output.
If a next reply is needed, please attach the full output as a .txt file (maintains formatting).

You can try increasing the map size (kmem_percent) and see if the problem goes away.
sysconfig -q generic kmem_percent ?

Re: Tru64 5.1 kernel memory management.

Darren Reed — Wed, 12 May 2004 10:35:36 GMT

The output wasn't reduced (apart from vmstat -M): what's happening is MALLOC(9) is failing and there are no console messages from Mr vmunix.

The actual code does something like this:
MALLOC(foo, void *, 16376, M_TEMP, M_NOWAIT)

This should be ok, according to the man page for MALLOC(9). Changing it to pass M_WAITOK for size > 4k has fixed the problem.

But what I find strange is why a 96MB alpha works with M_NOWAIT and why the 256MB alpha didn't. Is the kmem allocator different for the two variants?

I suppose this is more a question for a forum related kernel (driver) development on Tru64 but I couldn't see one of those..