Re: How much kernel memory is in 64-bit OS ?

[Andi Kleen]

Helge Hafting <helge.hafting@xxxxxxxxxxxxx> writes:

> The requirement for using a 4G/4G split is to have a processor
> that support 64-bit adressing as well as 32-bit backward compatibility.

s/64/36/. But it's actually not true: 4/4 works on 32bit phys non PAE 
system too (iirc Fedora forced it for some time even on unsuspecting
P-M/VIA C3/586 users who only do 32bit).

> > 2) how it is managed ?
> The kernel runs in 64-bit mode, offering the 4G/4G stuff for 32-bit
> processes.

No.

> 
> > 3) how HIGH_MEMORY concept is related here.
> high memory is a quirky way of supporting more than 4G on a 32-bit

More than ~900MB with a default split.

-Andi
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