[PATCH 00/12][RFC] Intial Kconfig Fragment Demo

[Andy Green]

On 03/09/2011 09:04 AM, Somebody in the thread at some point said:

>> I take it this magic of SMP or not is hidden in this config layering scheme
>> you mentioned and it isn't really using the same config for say igep0020 and
>
> No, it is in the black depths of ARM assembly and TBH, it is voodoo to
> me. Nothing to do with kernel config as such. The SMP kernel, at
> runtime, (binary) patches itself to convert locking primitives to
> no-ops in the UP case. Or something to the effect.

Hum my IGEP0020 config here has CONFIG_BROKEN_ON_SMP=y set so I guess 
this is to do with what you mentioned.

>> Panda.  In any event, there's a performance tradeoff running SMP kernel on
>> uniprocessor to consider too.
>
> Apparently, with this one-time patching (per boot) there isn't such a tradeoff.

OK thanks for the explanation.

>> Absolutely that's the future... in fact the bootloader should work the same
>> way with one per-arch bootloader that detects what it is running on at
>> runtime, and at that point device-specific point hwpacks become very thin or
>> non-existent and there's an epic reduction in how many different binaries
>> are needed to support many boards.
>
> I can hear the collective sighs of appreciation from distribution maintainers :)

^^

-Andy