Re: [RFC PATCH 0/1] Buddy allocator like folio split

[David Hildenbrand]

On 09.10.24 00:37, Zi Yan wrote:
> Hi all,

Hi!

> Matthew and I have discussed about a different way of splitting large
> folios. Instead of split one folio uniformly into the same order smaller
> ones, doing buddy allocator like split can reduce the total number of
> resulting folios, the amount of memory needed for multi-index xarray
> split, and keep more large folios after a split. In addition, both
> Hugh[1] and Ryan[2] had similar suggestions before.
>
> The patch is an initial implementation. It passes simple order-9 to
> lower order split tests for anonymous folios and pagecache folios.
> There are still a lot of TODOs to make it upstream. But I would like to gather
> feedbacks before that.

Interesting, but I don't see any actual users besides the debug/test 
interface wired up.

I assume ftruncate() / fallocate(PUNCH_HOLE) might be good use cases? 
For example, when punching 1M of a 2M folio, we can just leave a 1M 
folio in the pagecache.

Any other obvious users you have in mind?

--
Cheers,

David / dhildenb