Mixing amd64 kernel with i386 world

Ian Lepore ian at FreeBSD.org
Sat Sep 28 13:56:46 UTC 2013


On Sat, 2013-09-28 at 20:37 +1000, Peter Jeremy wrote:
> I have a system with 4GB RAM and hence need to use an amd64 kernel to use
> all the RAM (I can only access 3GB RAM with an i386 kernel).  OTOH, amd64
> processes are significantly (50-100%) larger than equivalent i386 processes
> and none none of the applications I'll be running on the system need to be
> 64-bit.
> 
> This implies that the optimal approach is an amd64 kernel with i386
> userland (I'm ignoring PAE as a useable approach).  I've successfully
> run i386 jails on amd64 systems so I know this mostly works.  I also
> know that there are some gotchas:
> - kdump needs to match the kernel
> - anything accessing /dev/mem or /dev/kmem (which implies anything that
>   uses libkvm) probably needs to match the kernel.
> 
> Has anyone investigated this approach?
> 

Why are you ignoring PAE?  It's been working for me for years.

-- Ian




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