Re: [PATCH v4 0/4] Make alloc_contig_range handle Hugetlb pages

[Oscar Salvador]

On Wed, Mar 17, 2021 at 10:48:31AM +0100, David Hildenbrand wrote:
> > I was preparing v5, and I wanted to be sure I understood you here.
> > 
> > Right you are that the in-use page check can be dropped, as those pages
> > can
> > be migrated away, and the Hugetlb page check can also be dropped since
> > isolate_migratepages_range is now capable of dealing with those kind of
> > pages.
> > 
> > > b) Similarly, check for gigantic pages and/or movability/migratability.
> > 
> > I lost you here.
> > 
> > isolate_or_dissolve_huge_page() already bails out on hugetlb-gigantic
> > pages.
> > 
> > Or do you mean to place an upfront check here? (hstate_is_gigantic())?
> 
> Yes. But I prefer a) and keeping it simple here -- just doing basic sanity
> checks (online, zone, PageReserved()) that are absolutely necessary.

Ok, I am probably dense as I understood as if you were lean towards having
a) + b).

That is what I have as the last patch of the patchset: