Re: Broken common.rmk change

[Robert Millan]

On Mon, Dec 07, 2009 at 11:50:33AM -0800, David Miller wrote:
> From: Robert Millan <address@hidden>
> Date: Mon, 7 Dec 2009 15:05:16 +0100
> 
> > On Sun, Dec 06, 2009 at 05:22:52PM -0800, David Miller wrote:
> >> From: Robert Millan <address@hidden>
> >> Date: Sun, 6 Dec 2009 14:10:26 +0100
> >> 
> >> > grub-mkconfig generates a grub.cfg that relies on UUIDs instead
> >> > of hardcoding, etc.
> >> 
> >> Well, for one thing I don't use initrd's for my Linux kernels,
> >> therefore specifying root devices via UUIDs isn't going to work.
> > 
> > I was referring to use of UUIDs internally by GRUB (e.g. the search command
> > instances grub-mkconfig generates).
> 
> Ok, but as noted in another thread this can make grub
> very slow on ieee1275 systems as we are going to look
> for the UUID on every ieee1275 device alias present and
> there can be tons of those.

I'm afraid I missed that thread.  In any case, we basically do/can do three
things to paliate that problem:

  - Cache the prepare_grub_to_access_device() calls at the shell/mkconfig
    layer (see util/grub.d/10_linux.in for an example).

  - Disk cache (kern/disk.c).

  - Adjust disk iteration order so that disks more likely to be the ones
    we're looking for show up first (e.g. on i386-pc we list hard disks
    before floppies or CD).  Note that UUID search aborts as soon as a
    match is found; it doesn't iterate the whole list.

More ideas welcome, of course :-)

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."