[RFC PATCH 3/6] mm/page_alloc: add an alloc_flags-aware folio allocator

[Gregory Price]

From: Brendan Jackman <brendan.jackman@xxxxxxxxxx>

The low-level page allocator accepts explicit allocator behavior flags,
but the folio helper hard-codes ALLOC_DEFAULT.

Add an MM-internal folio allocator that accepts alloc_flags. Keep the
existing exported folio and node interfaces unchanged as ALLOC_DEFAULT
wrappers.

No functional change intended.

Signed-off-by: Brendan Jackman <brendan.jackman@xxxxxxxxxx>
Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
---
 mm/page_alloc.c | 14 +++++++++++---
 mm/page_alloc.h |  6 ++++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b4a021fad183..feb9c64efd84 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5510,13 +5510,21 @@ struct page *alloc_pages_node_noprof(int nid, gfp_t gfp_mask, unsigned int order
 }
 EXPORT_SYMBOL(alloc_pages_node_noprof);
 
-struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order, int preferred_nid,
-		nodemask_t *nodemask)
+struct folio *__folio_alloc_flags_noprof(gfp_t gfp, unsigned int order,
+		int preferred_nid, nodemask_t *nodemask,
+		unsigned int alloc_flags)
 {
 	struct page *page = __alloc_pages_noprof(gfp | __GFP_COMP, order,
-					preferred_nid, nodemask, ALLOC_DEFAULT);
+					preferred_nid, nodemask, alloc_flags);
 	return page_rmappable_folio(page);
 }
+
+struct folio *__folio_alloc_noprof(gfp_t gfp, unsigned int order,
+		int preferred_nid, nodemask_t *nodemask)
+{
+	return __folio_alloc_flags_noprof(gfp, order, preferred_nid, nodemask,
+					 ALLOC_DEFAULT);
+}
 EXPORT_SYMBOL(__folio_alloc_noprof);
 
 /*
diff --git a/mm/page_alloc.h b/mm/page_alloc.h
index b9259deddb59..986e733b586e 100644
--- a/mm/page_alloc.h
+++ b/mm/page_alloc.h
@@ -258,6 +258,12 @@ struct page *__alloc_pages_noprof(gfp_t gfp, unsigned int order, int preferred_n
 		nodemask_t *nodemask, unsigned int alloc_flags);
 #define __alloc_pages(...)			alloc_hooks(__alloc_pages_noprof(__VA_ARGS__))
 
+struct folio *__folio_alloc_flags_noprof(gfp_t gfp, unsigned int order,
+		int preferred_nid, nodemask_t *nodemask,
+		unsigned int alloc_flags);
+#define __folio_alloc_flags(...) \
+	alloc_hooks(__folio_alloc_flags_noprof(__VA_ARGS__))
+
 extern void zone_pcp_reset(struct zone *zone);
 extern void zone_pcp_disable(struct zone *zone);
 extern void zone_pcp_enable(struct zone *zone);
-- 
2.55.0