On 2026/6/3 20:02, Usama Arif wrote:
On Tue, 2 Jun 2026 18:10:35 +0800 Muchun Song <[email protected]> wrote:Bootmem HugeTLB pages currently defer HVO setup to hugetlb_vmemmap_init_late(), because the optimization needs zone information. Now that zone initialization is available earlier, the bootmem HVO setup can be done directly from hugetlb_vmemmap_init_early(). This lets gigantic HugeTLB pages apply HVO as soon as they are allocated. Bootmem gigantic pages that span multiple zones are now filtered out when they are allocated, so the remaining bootmem gigantic pages seen by later hugetlb initialization are already zone-valid. As a result, hugetlb_vmemmap_init_late() no longer needs to handle bootmem HVO setup. Signed-off-by: Muchun Song <[email protected]> --- mm/hugetlb_vmemmap.c | 67 +++++++++----------------------------------- 1 file changed, 13 insertions(+), 54 deletions(-) diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index ea6af85bfec1..464578ee246e 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -745,6 +745,8 @@ static bool vmemmap_should_optimize_bootmem_page(struct huge_bootmem_page *m) return true; }+static struct zone *pfn_to_zone(unsigned nid, unsigned long pfn);+ /* * Initialize memmap section for a gigantic page, HVO-style. */ @@ -752,6 +754,7 @@ void __init hugetlb_vmemmap_init_early(int nid) { unsigned long psize, paddr, section_size; unsigned long ns, i, pnum, pfn, nr_pages; + unsigned long start, end; struct huge_bootmem_page *m = NULL; void *map;@@ -761,6 +764,8 @@ void __init hugetlb_vmemmap_init_early(int nid)section_size = (1UL << PA_SECTION_SHIFT);list_for_each_entry(m, &huge_boot_pages[nid], list) {+ struct zone *zone; + if (!vmemmap_should_optimize_bootmem_page(m)) continue;@@ -769,6 +774,14 @@ void __init hugetlb_vmemmap_init_early(int nid)paddr = virt_to_phys(m); pfn = PHYS_PFN(paddr); map = pfn_to_page(pfn); + start = (unsigned long)map; + end = start + hugetlb_vmemmap_size(m->hstate); + zone = pfn_to_zone(nid, pfn); + + if (vmemmap_populate_hvo(start, end, huge_page_order(m->hstate), + zone, HUGETLB_VMEMMAP_RESERVE_SIZE)) + panic("Failed to allocate memmap for HugeTLB page\n");The replaced hugetlb_vmemmap_init_late() path used to fall back to vmemmap_populate() if vmemmap_populate_hvo() returned an error and just lost the HVO optimization for that page. The new path panics on any non-zero return. Is the panic intended, given that vmemmap_populate_hvo() returns -ENOMEM on allocation failure and HVO is normally treated as an optimization rather than a hard requirement?
This is intentional; see patch 6: mm/sparse: Panic on memmap and usemap allocation failure We already panic on OOM anyway. Muchun, Thanks.
+ memmap_boot_pages_add(DIV_ROUND_UP(HUGETLB_VMEMMAP_RESERVE_SIZE, PAGE_SIZE));pnum = pfn_to_section_nr(pfn);ns = psize / section_size; @@ -800,60 +813,6 @@ static struct zone *pfn_to_zone(unsigned nid, unsigned long pfn)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); - 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); - 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--2.54.0
