+ mm-mempolicy-add-alloc_frozen_pages.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/mempolicy: add alloc_frozen_pages()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-mempolicy-add-alloc_frozen_pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mempolicy-add-alloc_frozen_pages.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm/mempolicy: add alloc_frozen_pages()
Date: Mon, 25 Nov 2024 21:01:46 +0000

Provide an interface to allocate pages from the page allocator without
incrementing their refcount.  This saves an atomic operation on free,
which may be beneficial to some users (eg slab).

Link: https://lkml.kernel.org/r/20241125210149.2976098-15-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Mel Gorman <mgorman@techsinguularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/internal.h  |   12 +++++++++++
 mm/mempolicy.c |   49 ++++++++++++++++++++++++++++++-----------------
 2 files changed, 44 insertions(+), 17 deletions(-)

--- a/mm/internal.h~mm-mempolicy-add-alloc_frozen_pages
+++ a/mm/internal.h
@@ -747,6 +747,18 @@ struct page *__alloc_frozen_pages_noprof
 void free_frozen_pages(struct page *page, unsigned int order);
 void free_unref_folios(struct folio_batch *fbatch);
 
+#ifdef CONFIG_NUMA
+struct page *alloc_frozen_pages_noprof(gfp_t, unsigned int order);
+#else
+static inline struct page *alloc_frozen_pages_noprof(gfp_t gfp, unsigned int order)
+{
+	return __alloc_frozen_pages_noprof(gfp, order, numa_node_id(), NULL);
+}
+#endif
+
+#define alloc_frozen_pages(...) \
+	alloc_hooks(alloc_frozen_pages_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);
--- a/mm/mempolicy.c~mm-mempolicy-add-alloc_frozen_pages
+++ a/mm/mempolicy.c
@@ -2205,9 +2205,9 @@ static struct page *alloc_pages_preferre
 	 */
 	preferred_gfp = gfp | __GFP_NOWARN;
 	preferred_gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL);
-	page = __alloc_pages_noprof(preferred_gfp, order, nid, nodemask);
+	page = __alloc_frozen_pages_noprof(preferred_gfp, order, nid, nodemask);
 	if (!page)
-		page = __alloc_pages_noprof(gfp, order, nid, NULL);
+		page = __alloc_frozen_pages_noprof(gfp, order, nid, NULL);
 
 	return page;
 }
@@ -2253,8 +2253,9 @@ static struct page *alloc_pages_mpol(gfp
 			 * First, try to allocate THP only on local node, but
 			 * don't reclaim unnecessarily, just compact.
 			 */
-			page = __alloc_pages_node_noprof(nid,
-				gfp | __GFP_THISNODE | __GFP_NORETRY, order);
+			page = __alloc_frozen_pages_noprof(
+				gfp | __GFP_THISNODE | __GFP_NORETRY, order,
+				nid, NULL);
 			if (page || !(gfp & __GFP_DIRECT_RECLAIM))
 				return page;
 			/*
@@ -2266,7 +2267,7 @@ static struct page *alloc_pages_mpol(gfp
 		}
 	}
 
-	page = __alloc_pages_noprof(gfp, order, nid, nodemask);
+	page = __alloc_frozen_pages_noprof(gfp, order, nid, nodemask);
 
 	if (unlikely(pol->mode == MPOL_INTERLEAVE) && page) {
 		/* skip NUMA_INTERLEAVE_HIT update if numa stats is disabled */
@@ -2284,8 +2285,13 @@ static struct page *alloc_pages_mpol(gfp
 struct folio *folio_alloc_mpol_noprof(gfp_t gfp, unsigned int order,
 		struct mempolicy *pol, pgoff_t ilx, int nid)
 {
-	return page_rmappable_folio(alloc_pages_mpol(gfp | __GFP_COMP,
-							order, pol, ilx, nid));
+	struct page *page = alloc_pages_mpol(gfp | __GFP_COMP, order, pol,
+			ilx, nid);
+	if (!page)
+		return NULL;
+
+	set_page_refcounted(page);
+	return page_rmappable_folio(page);
 }
 
 /**
@@ -2320,6 +2326,21 @@ struct folio *vma_alloc_folio_noprof(gfp
 }
 EXPORT_SYMBOL(vma_alloc_folio_noprof);
 
+struct page *alloc_frozen_pages_noprof(gfp_t gfp, unsigned order)
+{
+	struct mempolicy *pol = &default_policy;
+
+	/*
+	 * No reference counting needed for current->mempolicy
+	 * nor system default_policy
+	 */
+	if (!in_interrupt() && !(gfp & __GFP_THISNODE))
+		pol = get_task_policy(current);
+
+	return alloc_pages_mpol(gfp, order, pol, NO_INTERLEAVE_INDEX,
+				       numa_node_id());
+}
+
 /**
  * alloc_pages - Allocate pages.
  * @gfp: GFP flags.
@@ -2336,17 +2357,11 @@ EXPORT_SYMBOL(vma_alloc_folio_noprof);
  */
 struct page *alloc_pages_noprof(gfp_t gfp, unsigned int order)
 {
-	struct mempolicy *pol = &default_policy;
+	struct page *page = alloc_frozen_pages_noprof(gfp, order);
 
-	/*
-	 * No reference counting needed for current->mempolicy
-	 * nor system default_policy
-	 */
-	if (!in_interrupt() && !(gfp & __GFP_THISNODE))
-		pol = get_task_policy(current);
-
-	return alloc_pages_mpol(gfp, order, pol, NO_INTERLEAVE_INDEX,
-				       numa_node_id());
+	if (page)
+		set_page_refcounted(page);
+	return page;
 }
 EXPORT_SYMBOL(alloc_pages_noprof);
 
_

Patches currently in -mm which might be from willy@infradead.org are

mm-page_alloc-cache-page_zone-result-in-free_unref_page.patch
mm-make-alloc_pages_mpol-static.patch
mm-page_alloc-export-free_frozen_pages-instead-of-free_unref_page.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-post_alloc_hook.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-prep_new_page.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-get_page_from_freelist.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_cpuset_fallback.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_may_oom.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_direct_compact.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_direct_reclaim.patch
mm-page_alloc-move-set_page_refcounted-to-callers-of-__alloc_pages_slowpath.patch
mm-page_alloc-move-set_page_refcounted-to-end-of-__alloc_pages.patch
mm-page_alloc-add-__alloc_frozen_pages.patch
mm-mempolicy-add-alloc_frozen_pages.patch
slab-allocate-frozen-pages.patch