On Tue 15-10-19 13:50:02, David Hildenbrand wrote:

On 15.10.19 13:47, Michal Hocko wrote:

quoted

On Tue 15-10-19 13:42:03, David Hildenbrand wrote:
[...]

quoted

quoted

-static bool pfn_range_valid_gigantic(struct zone *z,
-			unsigned long start_pfn, unsigned long nr_pages)
-{
-	unsigned long i, end_pfn = start_pfn + nr_pages;
-	struct page *page;
-
-	for (i = start_pfn; i < end_pfn; i++) {
-		if (!pfn_valid(i))
-			return false;
-
-		page = pfn_to_page(i);

Am I missing something or should here really be a pfn_to_online_page() here
instead of a pfn_valid() ?

http://lkml.kernel.org/r/20180423000943.GO17484@dhcp22.suse.cz

So we managed to add PageReserved(page) but not pfn_to_online_page(). But it
is the right thing to do? (or am I missing something?)

Yeah, pfn_to_online_page is better. But please note that this is an
optimistic check. The real check has to be done when isolating the
pageblock because things might change in the meantime.
-- 
Michal Hocko
SUSE Labs