[PATCH 06/10] x86/mm: stop marking page tables as MIX_SECTION_INFO
From: David Hildenbrand (Arm)
Date: Wed Jul 08 2026 - 10:21:32 EST
There is no good reason to mark boot page tables as MIX_SECTION_INFO: we
only free boot page tables when they are completely empty, and memory
offlining/hotunplug doesn't benefit from it in any way.
So just stop marking page tables as MIX_SECTION_INFO. In
free_pagetable(), we can now simply free reserved pages directly.
Signed-off-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
---
arch/x86/mm/init_64.c | 59 ++-------------------------------------------------
1 file changed, 2 insertions(+), 57 deletions(-)
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 82bb0384b8ab0..1b17dcf781e66 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1002,21 +1002,10 @@ int arch_add_memory(int nid, u64 start, u64 size,
static void __meminit free_pagetable(struct page *page)
{
- /* bootmem page has reserved flag */
- if (PageReserved(page)) {
-#ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE
- enum bootmem_type type = bootmem_type(page);
-
- if (type == MIX_SECTION_INFO)
- put_page_bootmem(page);
- else
- free_reserved_page(page);
-#else
+ if (PageReserved(page))
free_reserved_page(page);
-#endif
- } else {
+ else
pagetable_free(page_ptdesc(page));
- }
}
static void __meminit free_vmemmap_pages(struct page *page, unsigned int order,
@@ -1579,50 +1568,6 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
void register_page_bootmem_memmap(unsigned long section_nr,
struct page *start_page, unsigned long nr_pages)
{
- unsigned long addr = (unsigned long)start_page;
- unsigned long end = (unsigned long)(start_page + nr_pages);
- unsigned long next;
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
-
- for (; addr < end; addr = next) {
- pgd = pgd_offset_k(addr);
- if (pgd_none(*pgd)) {
- next = (addr + PAGE_SIZE) & PAGE_MASK;
- continue;
- }
- get_page_bootmem(section_nr, pgd_page(*pgd), MIX_SECTION_INFO);
-
- p4d = p4d_offset(pgd, addr);
- if (p4d_none(*p4d)) {
- next = (addr + PAGE_SIZE) & PAGE_MASK;
- continue;
- }
- get_page_bootmem(section_nr, p4d_page(*p4d), MIX_SECTION_INFO);
-
- pud = pud_offset(p4d, addr);
- if (pud_none(*pud)) {
- next = (addr + PAGE_SIZE) & PAGE_MASK;
- continue;
- }
- get_page_bootmem(section_nr, pud_page(*pud), MIX_SECTION_INFO);
-
- pmd = pmd_offset(pud, addr);
- if (pmd_none(*pmd)) {
- next = (addr + PAGE_SIZE) & PAGE_MASK;
- continue;
- }
-
- if (!boot_cpu_has(X86_FEATURE_PSE) || !pmd_leaf(*pmd)) {
- next = (addr + PAGE_SIZE) & PAGE_MASK;
- get_page_bootmem(section_nr, pmd_page(*pmd),
- MIX_SECTION_INFO);
- } else {
- next = pmd_addr_end(addr, end);
- }
- }
}
#endif
--
2.43.0