Re: Changing external kernel module results in rebuild of whole kernel

[Mike Looijmans <mike.looijmans@topic.nl>]

On 06-05-15 14:35, Richard Purdie wrote:
> On Wed, 2015-05-06 at 08:35 +0200, Mike Looijmans wrote:
>> Something in recent OE-core triggered a weird dependency "backfire".
>>
>> If I change a recipe for a kernel module (a bb recipe that does "inherit
>> module") this will trigger a rebuild of the whole kernel.
>>
>> This turns the 5-second job of just updating a single module into a several
>> minute workout for the build machine, and then causes boards to re-write the
>> kernel into flash needlessly when upgrading.
>>
>> I now see this on all projects using OE-core master. I can't really pin what
>> caused it though. Anyone else seen this?
>
> I have a suspicion this may be as a result of the changed kernel build
> process in 1.8.
>
> The idea there is that the modules depend on the kernel source and
> rather than taring up and then extracting a large (GB) sized sstate
> object, we just extract the original kernel source.
>
> So is the kernel really rebuilding, or, is it just extracting source for
> the kernel to build against? I noticed rm_work in your other post and
> this may also be some bad interaction between rm_work and the kernel
> build process changes.

Any things I can try or provide on this?

As things are now, I'd much prefer the "taring up and then extracting a large 
(GB) sized sstate object" option, since that at least worked correctly.

Mike.


Kind regards,

Mike Looijmans
System Expert

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