Re: [PATCH v6 00/33] Split ptdesc from struct page

[David Hildenbrand <david@xxxxxxxxxx>]

On 27.06.23 06:44, Hugh Dickins wrote:
> On Mon, 26 Jun 2023, Vishal Moola (Oracle) wrote:
>
> > The MM subsystem is trying to shrink struct page. This patchset
> > introduces a memory descriptor for page table tracking - struct ptdesc.
> ...
> >   39 files changed, 686 insertions(+), 455 deletions(-)
> I don't see the point of this patchset: to me it is just obfuscation of
> the present-day tight relationship between page table and struct page.
>
> Matthew already explained:
>
> > The intent is to get ptdescs to be dynamically allocated at some point
> > in the ~2-3 years out future when we have finished the folio project ...
> So in a kindly mood, I'd say that this patchset is ahead of its time.
> But I can certainly adapt to it, if everyone else sees some point to it.
I share your thoughts, that code churn which will help eventually in the 
far, far future (not wanting to sound too pessimistic, but it's not 
going to be there tomorrow ;) ).
However, if it's just the same as the other conversions we already did 
(e.g., struct slab), then I guess there is no reason to stop now -- the 
obfuscation already happened.
... or is there a difference regarding this conversion and the previous 
ones?
--
Cheers,

David / dhildenb