mm/page_alloc: add __alloc_frozen_pages()

Defer the initialisation of the page refcount to the new __alloc_pages()
wrapper and turn the old __alloc_pages() into __alloc_frozen_pages().

Link: https://lkml.kernel.org/r/20241125210149.2976098-14-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/internal.h

@@ -740,6 +740,10 @@ extern bool free_pages_prepare(struct page *page, unsigned int order);
 
 extern int user_min_free_kbytes;
 
+struct page *__alloc_frozen_pages_noprof(gfp_t, unsigned int order, int nid,
+		nodemask_t *);
+#define __alloc_frozen_pages(...) \
+	alloc_hooks(__alloc_frozen_pages_noprof(__VA_ARGS__))
 void free_frozen_pages(struct page *page, unsigned int order);
 void free_unref_folios(struct folio_batch *fbatch);
 

mm/page_alloc.c

@@ -4713,8 +4713,8 @@ EXPORT_SYMBOL_GPL(alloc_pages_bulk_noprof);
 /*
  * This is the 'heart' of the zoned buddy allocator.
  */
-struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order,
-				      int preferred_nid, nodemask_t *nodemask)
+struct page *__alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order,
+		int preferred_nid, nodemask_t *nodemask)
 {
 	struct page *page;
 	unsigned int alloc_flags = ALLOC_WMARK_LOW;
@@ -4770,14 +4770,24 @@ struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order,
 		free_frozen_pages(page, order);
 		page = NULL;
 	}
-	if (page)
-		set_page_refcounted(page);
 
 	trace_mm_page_alloc(page, order, alloc_gfp, ac.migratetype);
 	kmsan_alloc_page(page, order, alloc_gfp);
 
 	return page;
 }
+EXPORT_SYMBOL(__alloc_frozen_pages_noprof);
+
+struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order,
+		int preferred_nid, nodemask_t *nodemask)
+{
+	struct page *page;
+
+	page = __alloc_frozen_pages_noprof(gfp, order, preferred_nid, nodemask);
+	if (page)
+		set_page_refcounted(page);
+	return page;
+}
 EXPORT_SYMBOL(__alloc_pages_noprof);
 
 struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order, int preferred_nid,