Re: [PATCH v5 5/5] mm,page_alloc: Drop unnecessary checks from pfn_range_valid_contig

[David Hildenbrand]

On 17.03.21 15:31, Michal Hocko wrote:
> On Wed 17-03-21 12:12:51, Oscar Salvador wrote:
> > pfn_range_valid_contig() bails out when it finds an in-use page or a
> > hugetlb page, among other things.
> > We can drop the in-use page check since __alloc_contig_pages can migrate
> > away those pages, and the hugetlb page check can go too since
> > isolate_migratepages_range is now capable of dealing with hugetlb pages.
> > Either way, those checks are racy so let the end function handle it
> > when the time comes.
>
> I haven't realized PageHuge check is done this early. This means that
> previous patches are not actually active until now which is not really
> greate for bisectability. Can we remove the HugePage check earlier?

alloc_contig_pages() vs. alloc_contig_range(). The patches are active 
for virtio-mem and CMA AFAIKS.

--
Thanks,

David / dhildenb