[PATCH 01/12] mm: hugetlb_vmemmap: remove HugeTLB-specific vmemmap optimization macros
From: Muchun Song
Date: Tue Oct 20 2026 - 07:57:24 EST
Vmemmap optimization is no longer HugeTLB-specific, so the remaining
HugeTLB-local reserve macros are redundant.
Replace them with the generic definitions to remove duplication and keep
the HugeTLB vmemmap code aligned with the common optimization macros.
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
include/linux/vmemmap-optimization.h | 4 ++--
mm/hugetlb.c | 4 ++--
mm/hugetlb_vmemmap.c | 8 ++++----
mm/hugetlb_vmemmap.h | 10 ++--------
4 files changed, 10 insertions(+), 16 deletions(-)
diff --git a/include/linux/vmemmap-optimization.h b/include/linux/vmemmap-optimization.h
index fa9e9abd6656..065840f3c241 100644
--- a/include/linux/vmemmap-optimization.h
+++ b/include/linux/vmemmap-optimization.h
@@ -27,8 +27,8 @@
/* 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_SIZE (VMEMMAP_OPTIMIZATION_PAGES * PAGE_SIZE)
+#define VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES (VMEMMAP_OPTIMIZATION_SIZE / sizeof(struct page))
#define VMEMMAP_OPTIMIZATION_MIN_ORDER (ilog2(VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES) + 1)
#ifdef CONFIG_VMEMMAP_OPTIMIZATION
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index b37d7d0db7fc..6a011b627986 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3308,7 +3308,7 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h,
* be no contention.
*/
hugetlb_folio_init_tail_vmemmap(folio, h,
- HUGETLB_VMEMMAP_RESERVE_PAGES,
+ VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES,
pages_per_huge_page(h));
}
hugetlb_bootmem_init_migratetype(folio, h);
@@ -3348,7 +3348,7 @@ static void __init gather_bootmem_prealloc_node(unsigned long nid)
WARN_ON(folio_ref_count(folio) != 1);
hugetlb_folio_init_vmemmap(folio, h,
- HUGETLB_VMEMMAP_RESERVE_PAGES);
+ VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES);
init_new_hugetlb_folio(folio);
if (vmemmap_optimizable_order(pfn_to_section_compound_order(pfn)))
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 0057fa2a16a8..1105aa925acc 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -406,7 +406,7 @@ static int __hugetlb_vmemmap_restore_folio(const struct hstate *h,
vmemmap_start = (unsigned long)&folio->page;
vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h);
- vmemmap_start += HUGETLB_VMEMMAP_RESERVE_SIZE;
+ vmemmap_start += VMEMMAP_OPTIMIZATION_SIZE;
/*
* The pages which the vmemmap virtual address range [@vmemmap_start,
@@ -613,7 +613,7 @@ static void __hugetlb_vmemmap_optimize_folios(struct hstate *h,
spfn = (unsigned long)&folio->page;
epfn = spfn + hugetlb_vmemmap_size(h);
vmemmap_wrprotect_hvo(spfn, epfn, folio_nid(folio),
- HUGETLB_VMEMMAP_RESERVE_SIZE);
+ VMEMMAP_OPTIMIZATION_SIZE);
continue;
}
@@ -701,8 +701,8 @@ static int __init hugetlb_vmemmap_init(void)
{
const struct hstate *h;
- /* HUGETLB_VMEMMAP_RESERVE_SIZE should cover all used struct pages */
- BUILD_BUG_ON(__NR_USED_SUBPAGE > HUGETLB_VMEMMAP_RESERVE_PAGES);
+ /* VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES should cover all used struct pages */
+ BUILD_BUG_ON(__NR_USED_SUBPAGE > VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES);
for_each_hstate(h) {
if (hugetlb_vmemmap_optimizable(h)) {
diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h
index 464192e32dec..749c7371ceec 100644
--- a/mm/hugetlb_vmemmap.h
+++ b/mm/hugetlb_vmemmap.h
@@ -9,13 +9,7 @@
#ifndef _LINUX_HUGETLB_VMEMMAP_H
#define _LINUX_HUGETLB_VMEMMAP_H
#include <linux/hugetlb.h>
-
-/*
- * Reserve one vmemmap page, all vmemmap addresses are mapped to it. See
- * Documentation/mm/vmemmap_dedup.rst.
- */
-#define HUGETLB_VMEMMAP_RESERVE_SIZE PAGE_SIZE
-#define HUGETLB_VMEMMAP_RESERVE_PAGES (HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page))
+#include <linux/vmemmap-optimization.h>
#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
int hugetlb_vmemmap_restore_folio(const struct hstate *h, struct folio *folio);
@@ -38,7 +32,7 @@ static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h)
*/
static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
{
- int size = hugetlb_vmemmap_size(h) - HUGETLB_VMEMMAP_RESERVE_SIZE;
+ int size = hugetlb_vmemmap_size(h) - VMEMMAP_OPTIMIZATION_SIZE;
if (!is_power_of_2(sizeof(struct page)))
return 0;
--
2.54.0