Re: [PATCH v19 02/13] x86/setup: Use parse_crashkernel_high_low() to simplify code

[Dave Young]

On 12/29/21 at 11:03am, Borislav Petkov wrote:
> On Wed, Dec 29, 2021 at 03:27:48PM +0800, Dave Young wrote:
> > So I think you can unify the parse_crashkernel* in x86 first with just
> > one function.  And leave the further improvements to later work. But
> > let's see how Boris think about this.
> 
> Well, I think this all unnecessary work. Why?
> 
> If the goal is to support crashkernel...high,low on arm64, then you
> should simply *copy* the functionality on arm64 and be done with it.
> 
> Unification is done by looking at code which is duplicated across
> architectures and which has been untouched for a while now, i.e., no
> new or arch-specific changes are going to it so a unification can be
> as simple as trivially switching the architectures to call a generic
> function.
> 
> What this does is carve out the "generic" parts and then try not to
> break existing usage.
> 
> Which is a total waste of energy and resources. And it is casting that
> functionality in stone so that when x86 wants to change something there,
> it should do it in a way not to break arm64. And I fail to see the
> advantage of all that. Code sharing ain't it.
> 
> So what it should do is simply copy the necessary code to arm64.
> Unifications can always be done later, when the dust settles.

I think I agree with you about the better way is to doing some
improvements so that arches can logically doing things better.  I can
leave with the way I suggested although it is not the best.  But I think
Leizhen needs a clear direction about how to do it. It is very clear
now.  See how he will handle this. 

> 
> IMNSVHO.
> 
> -- 
> Regards/Gruss,
>     Boris.
> 
> https://people.kernel.org/tglx/notes-about-netiquette
>