On Tue 15-10-19 14:51:41, Anshuman Khandual wrote:
[...]

+/**
+ * alloc_gigantic_page_order() -- tries to allocate given order of pages
+ * @order:	allocation order (greater than MAX_ORDER)
+ * @gfp_mask:	GFP mask to use during compaction
+ * @nid:	allocation node
+ * @nodemask:	allocation nodemask
+ *
+ * This routine is an wrapper around alloc_contig_range() which scans over
+ * all zones on an applicable zonelist to find a contiguous pfn range which
+ * can the be allocated with alloc_contig_range(). This routine is intended
+ * to be used for allocations greater than MAX_ORDER.
+ *
+ * Return: page on success or NULL on failure. On success a memory block
+ * of 'order' starting with 'page' has been allocated successfully. Memory
+ * allocated here needs to be freed with free_contig_range().
+ */
+struct page *alloc_gigantic_page_order(unsigned int order, gfp_t gfp_mask,
+				       int nid, nodemask_t *nodemask)

One of the objections when Mike has proposed a similar thing last year
was that the interface shouldn't be order bases
http://lkml.kernel.org/r/20180423000943.GO17484@dhcp22.suse.cz

Order based API makes sense for the buddy allocator but why should we
restrict sizes like that for an allocator that is capable to allocate
arbitrary page sized requests?
-- 
Michal Hocko
SUSE Labs