Pools vs kmem_alloc [Was: CVS commit: src/sys/kern]

[Simon Burge <simonb%NetBSD.org@localhost>]

Andrew Doran wrote:

> Module Name:  src
> Committed By: ad
> Date:         Mon Mar 17 00:52:56 UTC 2008
> 
> Modified Files:
> 
>       src/sys/kern: kern_proc.c
> 
> Log Message:
> 
> Process group and session structures are allocated so infrequently that
> there is no point having seperate caches for them. Just use kmem_alloc().

Is there a rule of thumb for what "infrequent" means?  nbmail for example
is allocating about 1.5 of these a second, while my main workstation here
about once every 10 seconds.

Perhaps we could add some sort of discussion in memoryallocators(9)
for when to choose each allocator...

Cheers,
Simon.