Re: [PATCH 09/13] mm/powerpc: Redefine pXd_huge() with pXd_leaf()

[Christophe Leroy]

Le 20/03/2024 à 17:09, Peter Xu a écrit :
> On Wed, Mar 20, 2024 at 06:16:43AM +0000, Christophe Leroy wrote:
>> At the first place that was to get a close fit between hardware
>> pagetable topology and linux pagetable topology. But obviously we
>> already stepped back for 512k pages, so let's go one more step aside and
>> do similar with 8M pages.
>>
>> I'll give it a try and see how it goes.
> 
> So you're talking about 8M only for 8xx, am I right?

Yes I am.

> 
> There seem to be other PowerPC systems use hugepd.  Is it possible that we
> convert all hugepd into cont_pte form?

Indeed.

Seems like we have hugepd for book3s/64 and for nohash.

For book3s I don't know, may Aneesh can answer.

For nohash I think it should be possible because TLB misses are handled 
by software. Even the e6500 which has a hardware tablewalk falls back on 
software walk when it is a hugepage IIUC.

Christophe