ZFS kmem_map too small.

[Pawel Jakub Dawidek]

On Tue, Oct 09, 2007 at 12:28:09PM -0700, Darren Reed wrote:
> Pawel Jakub Dawidek wrote:
> >...
> >
> >For i386 one has to set, eg. 'options KVA_PAGES=512' to the kernel
> >config to be able to define kmem larger than ~700MB. I guess you're
> >running amd64, maybe there is similar requirement?
> >  
> 
> Given how much RAM PCs have these days, why isn't this a default for 
> GENERIC?
> 
> Or why isn't it at least a tunable rather than an option?

This may be a good reason - today's PCs have a lot of RAM and KVA_PAGES
splits address space between userland and kernel - the more address
space for the kernel, the less address space for the userland.
KVA_PAGES=512 splits 4GB address space in half, so userland processes
can address at most 2GB of memory.

-- 
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd at FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!
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