From 7bfc04d6bd8d7fc60436cd8914928e8b80696439 Mon Sep 17 00:00:00 2001 From: "David Hildenbrand (Arm)" Date: Thu, 16 Jul 2026 16:51:04 +0200 Subject: x86/mm: stop marking vmemmap as SECTION_INFO We added the whole bootmem registration machinery in commit 04753278769f ("memory hotplug: register section/node id to free"). The main use case was to remember to which memory section memmap pages belonged, so the memmap could be handled accordingly when freeing memory. However, all that machinery is not required anymore: a memory section can only get offlined if *all* pages can get offlined; and it can only get unplugged once offline. If some of these pages are unmovable memmap pages: bad luck, doesn't work. Offlining will fail. Further, a lot of this machinery was required for pre-vmemmap support. Now we only support the vmemmap with memory hotplug. So the whole machinery is useless today. Let's start by removing the last pieces by first stopping to mark vmemmap pages as SECTION_INFO. In free_vmemmap_pages(), we can now always just free the reserved pages directly. Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-5-4afc76c73d61@kernel.org Signed-off-by: David Hildenbrand (Arm) Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Dave Hansen Cc: Alexander Gordeev Cc: Andy Lutomirski Cc: "Borislav Petkov (AMD)" Cc: Brendan Jackman Cc: Brendan Jackman Cc: Christian Borntraeger Cc: Gerald Schaefer Cc: Heiko Carstens Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Johannes Weiner Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Muchun Song Cc: Oscar Salvador Cc: Peter Zijlstra Cc: Suren Baghdasaryan Cc: Sven Schnelle Cc: Vasily Gorbik Cc: Vlastimil Babka Cc: Zi Yan Signed-off-by: Andrew Morton --- arch/x86/mm/init_64.c | 30 ++++-------------------------- 1 file changed, 4 insertions(+), 26 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 320e742b0bb3..82bb0384b8ab 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1024,19 +1024,12 @@ static void __meminit free_vmemmap_pages(struct page *page, unsigned int order, { unsigned long nr_pages = 1u << order; - if (altmap) { + if (altmap) vmem_altmap_free(altmap, nr_pages); - } else if (PageReserved(page)) { - if (IS_ENABLED(CONFIG_HAVE_BOOTMEM_INFO_NODE) && - bootmem_type(page) == SECTION_INFO) { - while (nr_pages--) - put_page_bootmem(page++); - } else { - free_reserved_pages(page, order); - } - } else { + else if (PageReserved(page)) + free_reserved_pages(page, order); + else __free_pages(page, order); - } } static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd) @@ -1593,12 +1586,8 @@ void register_page_bootmem_memmap(unsigned long section_nr, p4d_t *p4d; pud_t *pud; pmd_t *pmd; - unsigned int nr_pmd_pages; - struct page *page; for (; addr < end; addr = next) { - pte_t *pte = NULL; - pgd = pgd_offset_k(addr); if (pgd_none(*pgd)) { next = (addr + PAGE_SIZE) & PAGE_MASK; @@ -1630,19 +1619,8 @@ void register_page_bootmem_memmap(unsigned long section_nr, next = (addr + PAGE_SIZE) & PAGE_MASK; get_page_bootmem(section_nr, pmd_page(*pmd), MIX_SECTION_INFO); - - pte = pte_offset_kernel(pmd, addr); - if (pte_none(*pte)) - continue; - get_page_bootmem(section_nr, pte_page(*pte), - SECTION_INFO); } else { next = pmd_addr_end(addr, end); - nr_pmd_pages = (next - addr) >> PAGE_SHIFT; - page = pmd_page(*pmd); - while (nr_pmd_pages--) - get_page_bootmem(section_nr, page++, - SECTION_INFO); } } } -- cgit v1.2.3