Re: [PATCH] initramfs: Allow rootfs to use tmpfs instead of ramfs

[Rob Landley <rob@landley.net>]

I am totally out of the loop here.  (BusyBox has been taking up all my time 
for months now...)

I thought rootfs already would be tmpfs whenever that was compiled into the 
kernel, but I suspect the kernel I was looking at to come to that conclusion 
wasn't vanilla.  Still, that implies this isn't the first patch out there to 
do this...

On Sunday 30 July 2006 2:48 pm, H. Peter Anvin wrote:
> There is some justification: embedded people would like to load 
> inittmpfs and then continue running.

Yup.  Embedded people who generally have no swap anyway.  (Swap to flash is a 
bad idea.)  However, I believe what they were after was the ability to limit 
the filesystem size so runaway logs don't trigger the OOM killer.

> The main issue -- which I am not sure what effect this patch has -- is 
> that we would really like to move initramfs initialization even earlier 
> in the kernel, so that it can include firmware loading for built-in 
> device drivers, for example.

I remember this was "pending" late last year.  Thought it had made it into 
2.6.16 or so.  I need _way_ more time to read the kernel list.  (I'm 50,197 
messages behind.  That's just silly...)

> Thus, if this patch makes it harder to push initramfs initialization 
> earlier, it's probably a bad thing.  If not, the author of the patch 
> really needs to explain why it works and why it doesn't add new 
> dependencies to the initialization order.
> 
> Saying "this is a trivial patch" and pushing it on the -stable tree 
> doesn't inspire too much confidence, as initialization is subtle.

It doesn't look like -stable material to me either.  It might be small enough 
to add to the current -devel cycle, but that's not my call.

Is there any current documentation on the kernel's init sequence other than 
reading init/main.c and friends?

> 	-hpa

Rob
-- 
Never bet against the cheap plastic solution.