On 2021/12/29 18:46, Dave Young wrote: > 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. It's just a worry, there's uncertainty about whether it's going to be. I think the only thing that might change is the default value of "low_size". Of course, the alignment size and start address may also change, but most of them can be controlled by macros. Chen Zhou and I tried to share the code because of a suggestion. After so many attempts, it doesn't seem to fit to make generic. Or maybe I haven't figured out a good solution yet. >> >> 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. Surviving, then pursuing ideals. I will put the patches that make arm64 support crashkernel...high,low to the front, then the parse_crashkernel() unification patches. Even if the second half of the patches is not ready for v5.18, the first half of the patches is ready. > >> >> IMNSVHO. >> >> -- >> Regards/Gruss, >> Boris. >> >> https://people.kernel.org/tglx/notes-about-netiquette >> > > . > -- Regards, Zhen Lei
