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

[Michal Hocko]

On Wed 17-03-21 15:36:35, David Hildenbrand wrote:
> 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.

yeah, I meant to say "are not actually fully active".
-- 
Michal Hocko
SUSE Labs