[PATCH 17/49] mm: remove sparse_vmemmap_init_nid_late()

Muchun Song
2026-04-05T12:55:16Z

After deferring hugetlb bootmem allocation until after free_area_init()
and checking cross-zone pages during allocation, the hugetlb_vmemmap_init_late()
function is no longer needed:

1. hugetlb_bootmem_alloc() is now called after free_area_init(), so zone
information is available during bootmem huge page allocation.
2. During alloc_bootmem(), cross-zone pages are identified and marked with
HUGE_BOOTMEM_ZONES_VALID flag.
3. After allocation, hugetlb_free_cross_zone_pages() frees those pages that
intersect multiple zones.

Since cross-zone pages are already handled in the allocation path, the late-stage
validation in hugetlb_vmemmap_init_late() is redundant and can be removed.

Also, the sparse_vmemmap_init_nid_late() function is now empty and unused.
Remove it to clean up the code.

Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
include/linux/hugetlb.h | 2 --
include/linux/mmzone.h | 7 -----
mm/hugetlb.c | 70 -----------------------------------------
mm/hugetlb_vmemmap.c | 58 ----------------------------------
mm/hugetlb_vmemmap.h | 5 ---
mm/sparse-vmemmap.c | 11 -------
mm/sparse.c | 2 --
7 files changed, 155 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 9c098a02a09e..23d95ed6121f 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -699,8 +699,6 @@ struct huge_bootmem_page {
#define HUGE_BOOTMEM_ZONES_VALID 0x0002
#define HUGE_BOOTMEM_CMA 0x0004

-bool hugetlb_bootmem_page_zones_valid(int nid, struct huge_bootmem_page *m);
-
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);
void wait_for_freed_hugetlb_folios(void);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a071f1a0e242..8ee9dc60120a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -2153,8 +2153,6 @@ static inline int preinited_vmemmap_section(const struct mem_section *section)
}

void sparse_vmemmap_init_nid_early(int nid);
-void sparse_vmemmap_init_nid_late(int nid);
-
#else
static inline int preinited_vmemmap_section(const struct mem_section *section)
{
@@ -2163,10 +2161,6 @@ static inline int preinited_vmemmap_section(const struct mem_section *section)
static inline void sparse_vmemmap_init_nid_early(int nid)
{
}
-
-static inline void sparse_vmemmap_init_nid_late(int nid)
-{
-}
#endif

static inline int online_section_nr(unsigned long nr)
@@ -2371,7 +2365,6 @@ static inline unsigned long next_present_section_nr(unsigned long section_nr)

#else
#define sparse_vmemmap_init_nid_early(_nid) do {} while (0)
-#define sparse_vmemmap_init_nid_late(_nid) do {} while (0)
#define pfn_in_present_section pfn_valid
#endif /* CONFIG_SPARSEMEM */

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 238495fd04e4..a00c9f3672b7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -58,7 +58,6 @@ struct hstate hstates[HUGE_MAX_HSTATE];

__initdata nodemask_t hugetlb_bootmem_nodes;
__initdata struct list_head huge_boot_pages[MAX_NUMNODES];
-static unsigned long hstate_boot_nrinvalid[HUGE_MAX_HSTATE] __initdata;

/*
* Due to ordering constraints across the init code for various
@@ -3254,57 +3253,6 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h,
}
}

-bool __init hugetlb_bootmem_page_zones_valid(int nid,
- struct huge_bootmem_page *m)
-{
- unsigned long start_pfn;
- bool valid;
-
- if (m->flags & HUGE_BOOTMEM_ZONES_VALID) {
- /*
- * Already validated, skip check.
- */
- return true;
- }
-
- if (hugetlb_bootmem_page_earlycma(m)) {
- valid = cma_validate_zones(m->cma);
- goto out;
- }
-
- start_pfn = virt_to_phys(m) >> PAGE_SHIFT;
-
- valid = !pfn_range_intersects_zones(nid, start_pfn,
- pages_per_huge_page(m->hstate));
-out:
- if (!valid)
- hstate_boot_nrinvalid[hstate_index(m->hstate)]++;
-
- return valid;
-}
-
-/*
- * Free a bootmem page that was found to be invalid (intersecting with
- * multiple zones).
- *
- * Since it intersects with multiple zones, we can't just do a free
- * operation on all pages at once, but instead have to walk all
- * pages, freeing them one by one.
- */
-static void __init hugetlb_bootmem_free_invalid_page(int nid, struct page *page,
- struct hstate *h)
-{
- unsigned long npages = pages_per_huge_page(h);
- unsigned long pfn;
-
- while (npages--) {
- pfn = page_to_pfn(page);
- __init_page_from_nid(pfn, nid);
- free_reserved_page(page);
- page++;
- }
-}
-
/*
* Put bootmem huge pages into the standard lists after mem_map is up.
* Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
@@ -3320,17 +3268,6 @@ static void __init gather_bootmem_prealloc_node(unsigned long nid)
struct folio *folio = (void *)page;

h = m->hstate;
- if (!hugetlb_bootmem_page_zones_valid(nid, m)) {
- /*
- * Can't use this page. Initialize the
- * page structures if that hasn't already
- * been done, and give them to the page
- * allocator.
- */
- hugetlb_bootmem_free_invalid_page(nid, page, h);
- continue;
- }
-
/*
* It is possible to have multiple huge page sizes (hstates)
* in this list. If so, process each size separately.
@@ -3700,20 +3637,13 @@ static void __init hugetlb_init_hstates(void)
static void __init report_hugepages(void)
{
struct hstate *h;
- unsigned long nrinvalid;

for_each_hstate(h) {
char buf[32];

- nrinvalid = hstate_boot_nrinvalid[hstate_index(h)];
- h->max_huge_pages -= nrinvalid;
-
string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
pr_info("HugeTLB: registered %s page size, pre-allocated %ld pages\n",
buf, h->nr_huge_pages);
- if (nrinvalid)
- pr_info("HugeTLB: %s page size: %lu invalid page%s discarded\n",
- buf, nrinvalid, str_plural(nrinvalid));
pr_info("HugeTLB: %d KiB vmemmap can be freed for a %s page\n",
hugetlb_vmemmap_optimizable_size(h) / SZ_1K, buf);
}
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index e25c70453928..535f0369a496 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -807,64 +807,6 @@ void __init hugetlb_vmemmap_init_early(int nid)
m->flags |= HUGE_BOOTMEM_HVO;
}
}
-
-void __init hugetlb_vmemmap_init_late(int nid)
-{
- struct huge_bootmem_page *m, *tm;
- unsigned long phys, nr_pages, start, end;
- unsigned long pfn, nr_mmap;
- struct zone *zone = NULL;
- struct hstate *h;
- void *map;
-
- if (!READ_ONCE(vmemmap_optimize_enabled))
- return;
-
- list_for_each_entry_safe(m, tm, &huge_boot_pages[nid], list) {
- if (!(m->flags & HUGE_BOOTMEM_HVO))
- continue;
-
- phys = virt_to_phys(m);
- h = m->hstate;
- pfn = PHYS_PFN(phys);
- nr_pages = pages_per_huge_page(h);
- map = pfn_to_page(pfn);
- start = (unsigned long)map;
- end = start + nr_pages * sizeof(struct page);
-
- if (!hugetlb_bootmem_page_zones_valid(nid, m)) {
- /*
- * Oops, the hugetlb page spans multiple zones.
- * Remove it from the list, and populate it normally.
- */
- list_del(&m->list);
-
- vmemmap_populate(start, end, nid, NULL, NULL);
- nr_mmap = end - start;
- memmap_boot_pages_add(DIV_ROUND_UP(nr_mmap, PAGE_SIZE));
-
- memblock_phys_free(phys, huge_page_size(h));
- continue;
- }
-
- if (!zone || !zone_spans_pfn(zone, pfn))
- zone = pfn_to_zone(nid, pfn);
- if (WARN_ON_ONCE(!zone))
- continue;
-
- if (vmemmap_populate_hvo(start, end, huge_page_order(h), zone,
- HUGETLB_VMEMMAP_RESERVE_SIZE) < 0) {
- /* Fallback if HVO population fails */
- vmemmap_populate(start, end, nid, NULL, NULL);
- nr_mmap = end - start;
- } else {
- m->flags |= HUGE_BOOTMEM_ZONES_VALID;
- nr_mmap = HUGETLB_VMEMMAP_RESERVE_SIZE;
- }
-
- memmap_boot_pages_add(DIV_ROUND_UP(nr_mmap, PAGE_SIZE));
- }
-}
#endif

static const struct ctl_table hugetlb_vmemmap_sysctls[] = {
diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h
index 18b490825215..7ac49c52457d 100644
--- a/mm/hugetlb_vmemmap.h
+++ b/mm/hugetlb_vmemmap.h
@@ -29,7 +29,6 @@ void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_l
void hugetlb_vmemmap_optimize_bootmem_folios(struct hstate *h, struct list_head *folio_list);
#ifdef CONFIG_SPARSEMEM_VMEMMAP_PREINIT
void hugetlb_vmemmap_init_early(int nid);
-void hugetlb_vmemmap_init_late(int nid);
#endif

@@ -81,10 +80,6 @@ static inline void hugetlb_vmemmap_init_early(int nid)
{
}

-static inline void hugetlb_vmemmap_init_late(int nid)
-{
-}
-
static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
{
return 0;
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index b7201c235419..26cb55c12a83 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -581,17 +581,6 @@ void __init sparse_vmemmap_init_nid_early(int nid)
{
hugetlb_vmemmap_init_early(nid);
}
-
-/*
- * This is called just before the initialization of page structures
- * through memmap_init. Zones are now initialized, so any work that
- * needs to be done that needs zone information can be done from
- * here.
- */
-void __init sparse_vmemmap_init_nid_late(int nid)
-{
- hugetlb_vmemmap_init_late(nid);
-}
#endif

static void subsection_mask_set(unsigned long *map, unsigned long pfn,
diff --git a/mm/sparse.c b/mm/sparse.c
index d940b973df66..5fe0a7e66775 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -383,8 +383,6 @@ static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
}
sparse_usage_fini();
sparse_buffer_fini();
-
- sparse_vmemmap_init_nid_late(nid);
}

/*
--
2.20.1