Switching Fedora to pae kernel by default?

[Jeremy Katz]

On Monday, January 19 2009, Avi Kivity said:
> Jeremy Katz wrote:
>> That said, we currently do install the PAE kernel if you have 4 GB+ of
>> RAM[1].  Switching to it by default is problematic because then we're
>> back to using different kernels for different cases 
>
> You have that now, don't you?  One case for <4GB and one for >=4GB.   
> Worse, if you install more memory, the kernel doesn't see it.
>
> Downgrading your CPU to one which does not support PAE should be rare.

Yes, but at least the "running a different kernel" case is currently the
relatively rare one.

>> and it also makes
>> the 'what do you with the live image' case a lot more complex.
>
> I'd just go with PAE here.

Can't do so -- the live image is definitely used on a lot of hardware
that isn't PAE capable.  Many/most Pentium M's didn't support it, the OLPC 
doesn't[1].  And those are common hardware targets for the live image

>> The _real_ fix here is to get PAE runtime much like was finally done
>> with SMP :-)
>
> Patches, as they say, are welcome.  

Low-level x86 setup code isn't quite my forte...  Hence I go for
goading others into doing it ;-)

> But you could install both kernels  
> and have the bootloaded choose (sticks wax balls into ears).

Want to write code for syslinux and grub to do the auto-choosing?  Then
we also have to figure out a way to shoe-horn another 50 MB of stuff
into the already full live image

Jeremy