[PATCH v5 08/12] mm/sparse-vmemmap: move vmemmap optimization helpers to a public header
From: Muchun Song
Date: Sat Sep 26 2026 - 22:57:16 EST
The vmemmap optimization helpers currently live in mm/sparse.h,
which is an internal MM header. That works for MM code, but
prevents powerpc from using the same interfaces without including a
private header.
Move the declarations and inline helpers to vmemmap-optimization.h.
This is a preparatory change for powerpc, which has its own vmemmap
optimization implementation and needs to use the common vmemmap
optimization interfaces from architecture code.
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Acked-by: Qi Zheng <qi.zheng@xxxxxxxxx>
Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
---
v5:
- Move the VMEMMAP_OPTIMIZATION_* macros and MAX_FOLIO_VMEMMAP_ALIGN to
vmemmap-optimization.h
v4:
- Use the renamed VMEMMAP_OPTIMIZATION config in the public header
- Collect Acked-by from Mike Rapoport
v3:
- Update the subject and commit message to describe common vmemmap
optimization helpers
- Collect Acked-by from Qi Zheng
v2:
- Fix missing header dependencies.
---
MAINTAINERS | 1 +
arch/loongarch/include/asm/pgtable.h | 1 +
arch/riscv/mm/init.c | 1 +
include/linux/mmzone.h | 17 -----
include/linux/vmemmap-optimization.h | 109 +++++++++++++++++++++++++++
mm/hugetlb.c | 2 +-
mm/hugetlb_vmemmap.c | 2 +-
mm/sparse.h | 78 +------------------
8 files changed, 115 insertions(+), 96 deletions(-)
create mode 100644 include/linux/vmemmap-optimization.h
diff --git a/MAINTAINERS b/MAINTAINERS
index 7eae9228f547..6aa7308cb6c3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12096,6 +12096,7 @@ F: Documentation/mm/hugetlbfs_reserv.rst
F: Documentation/mm/vmemmap_dedup.rst
F: fs/hugetlbfs/
F: include/linux/hugetlb.h
+F: include/linux/vmemmap-optimization.h
F: include/trace/events/hugetlbfs.h
F: mm/hugetlb.c
F: mm/hugetlb_cgroup.c
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index cf29a4c8ac59..f87603135131 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -72,6 +72,7 @@
#include <linux/mm_types.h>
#include <linux/mmzone.h>
+#include <linux/vmemmap-optimization.h>
#include <asm/fixmap.h>
#include <asm/sparsemem.h>
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index fb37b0b67efe..857f9a55039c 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -22,6 +22,7 @@
#include <linux/hugetlb.h>
#include <linux/kfence.h>
#include <linux/execmem.h>
+#include <linux/vmemmap-optimization.h>
#include <asm/alternative.h>
#include <asm/fixmap.h>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index cd68c1904c91..65de3bb13eb3 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -96,23 +96,6 @@
#define MAX_FOLIO_NR_PAGES (1UL << MAX_FOLIO_ORDER)
-/*
- * HugeTLB Vmemmap Optimization (HVO) requires struct pages of the head page to
- * be naturally aligned with regard to the folio size.
- *
- * HVO which is only active if the size of struct page is a power of 2.
- */
-#define MAX_FOLIO_VMEMMAP_ALIGN \
- (IS_ENABLED(CONFIG_VMEMMAP_OPTIMIZATION) && \
- is_power_of_2(sizeof(struct page)) ? \
- MAX_FOLIO_NR_PAGES * sizeof(struct page) : 0)
-
-/* The number of retained vmemmap pages with HVO enabled. */
-#define VMEMMAP_OPTIMIZATION_PAGES 1
-#define VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES \
- (VMEMMAP_OPTIMIZATION_PAGES * PAGE_SIZE / sizeof(struct page))
-#define VMEMMAP_OPTIMIZATION_MIN_ORDER (ilog2(VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES) + 1)
-
enum migratetype {
MIGRATE_UNMOVABLE,
MIGRATE_MOVABLE,
diff --git a/include/linux/vmemmap-optimization.h b/include/linux/vmemmap-optimization.h
new file mode 100644
index 000000000000..bd0974b262a4
--- /dev/null
+++ b/include/linux/vmemmap-optimization.h
@@ -0,0 +1,109 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * vmemmap-optimization.h
+ *
+ * Generic vmemmap optimization declarations.
+ *
+ * Author: Muchun Song <songmuchun@xxxxxxxxxxxxx>
+ */
+#ifndef _LINUX_VMEMMAP_OPTIMIZATION_H
+#define _LINUX_VMEMMAP_OPTIMIZATION_H
+
+#include <linux/align.h>
+#include <linux/log2.h>
+#include <linux/mmdebug.h>
+#include <linux/mmzone.h>
+
+/*
+ * HugeTLB Vmemmap Optimization (HVO) requires struct pages of the head page to
+ * be naturally aligned with regard to the folio size.
+ *
+ * HVO which is only active if the size of struct page is a power of 2.
+ */
+#define MAX_FOLIO_VMEMMAP_ALIGN \
+ (IS_ENABLED(CONFIG_VMEMMAP_OPTIMIZATION) && \
+ is_power_of_2(sizeof(struct page)) ? \
+ MAX_FOLIO_NR_PAGES * sizeof(struct page) : 0)
+
+/* The number of retained vmemmap pages with HVO enabled. */
+#define VMEMMAP_OPTIMIZATION_PAGES 1
+#define VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES \
+ (VMEMMAP_OPTIMIZATION_PAGES * PAGE_SIZE / sizeof(struct page))
+#define VMEMMAP_OPTIMIZATION_MIN_ORDER (ilog2(VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES) + 1)
+
+#ifdef CONFIG_VMEMMAP_OPTIMIZATION
+static inline unsigned int section_compound_order(const struct mem_section *section)
+{
+ return section->compound_page_order;
+}
+
+static inline void section_set_compound_order(struct mem_section *section,
+ unsigned int order)
+{
+ VM_WARN_ON(section_compound_order(section) && order &&
+ section_compound_order(section) != order);
+ section->compound_page_order = order;
+}
+
+static inline void section_set_compound_order_range(unsigned long pfn,
+ unsigned long nr_pages, unsigned int order)
+{
+ unsigned long section_nr = pfn_to_section_nr(pfn);
+
+ if (!IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION))
+ return;
+
+ for (unsigned long i = 0; i < nr_pages / PAGES_PER_SECTION; i++)
+ section_set_compound_order(__nr_to_section(section_nr + i), order);
+}
+
+static inline unsigned int pfn_to_section_compound_order(unsigned long pfn)
+{
+ return section_compound_order(__pfn_to_section(pfn));
+}
+
+struct page *vmemmap_shared_tail_page(unsigned int order, struct zone *zone);
+#else
+static inline unsigned int section_compound_order(const struct mem_section *section)
+{
+ return 0;
+}
+
+static inline void section_set_compound_order(struct mem_section *section,
+ unsigned int order)
+{
+}
+
+static inline void section_set_compound_order_range(unsigned long pfn,
+ unsigned long nr_pages, unsigned int order)
+{
+}
+
+static inline unsigned int pfn_to_section_compound_order(unsigned long pfn)
+{
+ return 0;
+}
+#endif /* CONFIG_VMEMMAP_OPTIMIZATION */
+
+static inline bool vmemmap_optimizable_pfn(unsigned long pfn)
+{
+ const unsigned int order = pfn_to_section_compound_order(pfn);
+ const unsigned long nr_pages = 1UL << order;
+
+ if (!is_power_of_2(sizeof(struct page)))
+ return false;
+
+ return (pfn & (nr_pages - 1)) >= VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES;
+}
+
+static inline bool vmemmap_optimizable_order(unsigned int order)
+{
+ if (!IS_ENABLED(CONFIG_VMEMMAP_OPTIMIZATION))
+ return false;
+
+ if (!is_power_of_2(sizeof(struct page)))
+ return false;
+
+ return order >= VMEMMAP_OPTIMIZATION_MIN_ORDER;
+}
+#endif /* _LINUX_VMEMMAP_OPTIMIZATION_H */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index fd00141b089a..2003439ea13c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -38,6 +38,7 @@
#include <linux/mm_inline.h>
#include <linux/padata.h>
#include <linux/pgalloc.h>
+#include <linux/vmemmap-optimization.h>
#include <asm/page.h>
#include <asm/tlb.h>
@@ -52,7 +53,6 @@
#include "hugetlb_cma.h"
#include "hugetlb_internal.h"
#include "mm_init.h"
-#include "sparse.h"
#include <linux/page-isolation.h>
#define HUGE_BOOTMEM_ZONES_VALID BIT(0)
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 76765c97ff68..0057fa2a16a8 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -15,10 +15,10 @@
#include <linux/mmdebug.h>
#include <linux/pagewalk.h>
#include <linux/pgalloc.h>
+#include <linux/vmemmap-optimization.h>
#include <asm/tlbflush.h>
#include "hugetlb_vmemmap.h"
-#include "sparse.h"
/**
* struct vmemmap_remap_walk - walk vmemmap page table
diff --git a/mm/sparse.h b/mm/sparse.h
index 326ad43bb5c3..a5111087ee3a 100644
--- a/mm/sparse.h
+++ b/mm/sparse.h
@@ -9,80 +9,7 @@
#define __MM_SPARSE_H
#include <linux/mmzone.h>
-
-#ifdef CONFIG_VMEMMAP_OPTIMIZATION
-static inline unsigned int section_compound_order(const struct mem_section *section)
-{
- return section->compound_page_order;
-}
-
-static inline void section_set_compound_order(struct mem_section *section,
- unsigned int order)
-{
- VM_WARN_ON(section_compound_order(section) && order &&
- section_compound_order(section) != order);
- section->compound_page_order = order;
-}
-
-static inline void section_set_compound_order_range(unsigned long pfn,
- unsigned long nr_pages, unsigned int order)
-{
- unsigned long section_nr = pfn_to_section_nr(pfn);
-
- if (!IS_ALIGNED(pfn | nr_pages, PAGES_PER_SECTION))
- return;
-
- for (unsigned long i = 0; i < nr_pages / PAGES_PER_SECTION; i++)
- section_set_compound_order(__nr_to_section(section_nr + i), order);
-}
-
-static inline unsigned int pfn_to_section_compound_order(unsigned long pfn)
-{
- return section_compound_order(__pfn_to_section(pfn));
-}
-#else
-static inline unsigned int section_compound_order(const struct mem_section *section)
-{
- return 0;
-}
-
-static inline void section_set_compound_order(struct mem_section *section,
- unsigned int order)
-{
-}
-
-static inline void section_set_compound_order_range(unsigned long pfn,
- unsigned long nr_pages, unsigned int order)
-{
-}
-
-static inline unsigned int pfn_to_section_compound_order(unsigned long pfn)
-{
- return 0;
-}
-#endif
-
-static inline bool vmemmap_optimizable_pfn(unsigned long pfn)
-{
- const unsigned int order = pfn_to_section_compound_order(pfn);
- const unsigned long nr_pages = 1UL << order;
-
- if (!is_power_of_2(sizeof(struct page)))
- return false;
-
- return (pfn & (nr_pages - 1)) >= VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES;
-}
-
-static inline bool vmemmap_optimizable_order(unsigned int order)
-{
- if (!IS_ENABLED(CONFIG_VMEMMAP_OPTIMIZATION))
- return false;
-
- if (!is_power_of_2(sizeof(struct page)))
- return false;
-
- return order >= VMEMMAP_OPTIMIZATION_MIN_ORDER;
-}
+#include <linux/vmemmap-optimization.h>
/*
* mm/sparse.c
@@ -142,9 +69,6 @@ static inline void sparse_sections_init(void) {}
* mm/sparse-vmemmap.c
*/
#ifdef CONFIG_SPARSEMEM_VMEMMAP
-#ifdef CONFIG_VMEMMAP_OPTIMIZATION
-struct page *vmemmap_shared_tail_page(unsigned int order, struct zone *zone);
-#endif
void sparse_init_subsection_map(void);
int section_nr_vmemmap_pages(unsigned long pfn, unsigned long nr_pages,
struct vmem_altmap *altmap, struct dev_pagemap *pgmap);
--
2.54.0