[PATCH v2 35/69] mm/hugetlb: Remove HUGE_BOOTMEM_HVO

From: Muchun Song

Date: Wed May 13 2026 - 09:32:21 EST


The HUGE_BOOTMEM_HVO flag tracked whether a bootmem huge page had
already gone through the old early vmemmap optimization path.

Now that HugeTLB uses section-based vmemmap optimization, that state is
already reflected in the section order.

Remove HUGE_BOOTMEM_HVO and its helper, and use the section state
directly when deciding whether to mark a folio as vmemmap-optimized.

Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 5 ++---
include/linux/mmzone.h | 7 ++++++-
mm/hugetlb.c | 12 +-----------
mm/hugetlb_vmemmap.c | 2 --
4 files changed, 9 insertions(+), 17 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index dce8969961ea..18af8f304b95 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -695,9 +695,8 @@ struct huge_bootmem_page {
unsigned long flags;
};

-#define HUGE_BOOTMEM_HVO 0x0001
-#define HUGE_BOOTMEM_ZONES_VALID 0x0002
-#define HUGE_BOOTMEM_CMA 0x0004
+#define HUGE_BOOTMEM_ZONES_VALID BIT(0)
+#define HUGE_BOOTMEM_CMA BIT(1)

int isolate_or_dissolve_huge_folio(struct folio *folio, struct list_head *list);
int replace_free_hugepage_folios(unsigned long start_pfn, unsigned long end_pfn);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a60fd5785fa5..9b87d798a365 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -117,6 +117,11 @@
#define NR_OPTIMIZABLE_FOLIO_ORDERS \
(__NR_OPTIMIZABLE_FOLIO_ORDERS > 0 ? __NR_OPTIMIZABLE_FOLIO_ORDERS : 0)

+static inline bool order_vmemmap_optimizable(unsigned int order)
+{
+ return order >= OPTIMIZABLE_FOLIO_MIN_ORDER;
+}
+
enum migratetype {
MIGRATE_UNMOVABLE,
MIGRATE_MOVABLE,
@@ -2262,7 +2267,7 @@ static inline bool section_vmemmap_optimizable(const struct mem_section *section
if (!is_power_of_2(sizeof(struct page)))
return false;

- return section_order(section) >= OPTIMIZABLE_FOLIO_MIN_ORDER;
+ return order_vmemmap_optimizable(section_order(section));
}

#ifndef CONFIG_HAVE_ARCH_PFN_VALID
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 080f130017e3..abd79bb85b1c 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3169,11 +3169,6 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
prep_compound_head(&folio->page, huge_page_order(h));
}

-static bool __init hugetlb_bootmem_page_prehvo(struct huge_bootmem_page *m)
-{
- return m->flags & HUGE_BOOTMEM_HVO;
-}
-
static bool __init hugetlb_bootmem_page_earlycma(struct huge_bootmem_page *m)
{
return m->flags & HUGE_BOOTMEM_CMA;
@@ -3265,12 +3260,7 @@ static void __init gather_bootmem_prealloc_node(unsigned long nid)
OPTIMIZED_FOLIO_VMEMMAP_NR_STRUCT_PAGES);
init_new_hugetlb_folio(folio);

- if (hugetlb_bootmem_page_prehvo(m)) {
- /*
- * If pre-HVO was done, just set the
- * flag, the HVO code will then skip
- * this folio.
- */
+ if (order_vmemmap_optimizable(pfn_to_section_order(folio_pfn(folio)))) {
folio_set_hugetlb_vmemmap_optimized(folio);
section_set_order_range(folio_pfn(folio), folio_nr_pages(folio), 0);
}
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 730190390ba9..66362e553870 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -718,8 +718,6 @@ void __init hugetlb_vmemmap_optimize_bootmem_page(struct huge_bootmem_page *m)
return;

section_set_order_range(pfn, pages_per_huge_page(h), huge_page_order(h));
- if (section_vmemmap_optimizable(__pfn_to_section(pfn)))
- m->flags |= HUGE_BOOTMEM_HVO;
}

static const struct ctl_table hugetlb_vmemmap_sysctls[] = {
--
2.54.0