mm,page_alloc: drop unnecessary checks from pfn_range_valid_contig

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.

Link: https://lkml.kernel.org/r/20210419075413.1064-8-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 656f86a985546007e8c6b900e5b4b2959f596f17..80fa6e0f9ed997ba839b31c9b1129d20a47f5bec 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8898,12 +8898,6 @@ static bool pfn_range_valid_contig(struct zone *z, unsigned long start_pfn,
 
                if (PageReserved(page))
                        return false;
-
-               if (page_count(page) > 0)
-                       return false;
-
-               if (PageHuge(page))
-                       return false;
        }
        return true;
 }