Re: Broken common.rmk change

[Vladimir 'φ-coder/phcoder' Serbinenko]

Robert Millan wrote:
> 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 :-)
>
>   
Seth proposed a hinting technique:
search --fs_uuid ... -s root --hint hd0,1
then hd0,1 will be checked first and only on failure it will revert to
scanning


-- 
Regards
Vladimir 'φ-coder/phcoder' Serbinenko

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