ZFS kmem_map too small.

[Ivan Voras]

Pawel Jakub Dawidek wrote:
> Here are some updates:
> 
> I was able to reproduce the panic by rsyncing big files and trying
> bonnie++ test suggested in this thread.
> 
> Can you guys retry with this patch:
> 
> 	http://people.freebsd.org/~pjd/patches/vm_kern.c.2.patch
> 
> It's a hack, yes, but allows to mitigate the problem quite well. I'm
> looking for a solution that can be used for 7.0 before we find a better
> fix.

Your patch makes this configuration work: RELENG_7 on VMWare Server with
256 MB of memory, without any tuning to sysctl.conf and loader.conf.
This is as bad environment (wrt memory pressure and timings) as you can
get :)

With this patch the (virtual) machine survives portsnap fetch extract,
where before the patch it would soon panic with kmem_map too small.

You have my vote to commit it :)