From ed3a33cd73da485f9de4ecaeada5b5cf51c073ef Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Thu, 10 Sep 2026 14:32:44 +0800 Subject: mm/sparse-vmemmap: support section-based vmemmap accounting section_nr_vmemmap_pages() can account ordinary sections and DAX sections, but section-based vmemmap optimization stores the compound page order in struct mem_section and retains a different number of vmemmap pages. Teach section_nr_vmemmap_pages() to recognize section-based optimized sections and calculate their vmemmap page count from the stored compound page order and the HVO retained page count. Link: https://lore.kernel.org/20260910063256.64386-6-songmuchun@bytedance.com Signed-off-by: Muchun Song Signed-off-by: Andrew Morton Acked-by: Mike Rapoport (Microsoft) Acked-by: Qi Zheng Cc: David Hildenbrand (Arm) Cc: David Laight Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Oscar Salvador Cc: Suren Baghdasaryan Cc: Vlastimil Babka --- include/linux/mmzone.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 738bf3d27256..2c4f63e379da 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -107,8 +107,10 @@ is_power_of_2(sizeof(struct page)) ? \ MAX_FOLIO_NR_PAGES * sizeof(struct page) : 0) -/* The number of struct pages covered by the retained vmemmap pages with HVO enabled. */ -#define VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES (PAGE_SIZE / sizeof(struct page)) +/* The number of retained vmemmap pages with HVO enabled. */ +#define VMEMMAP_OPTIMIZATION_PAGES 1 +#define VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES \ + (VMEMMAP_OPTIMIZATION_PAGES * PAGE_SIZE / sizeof(struct page)) #define VMEMMAP_OPTIMIZATION_MIN_ORDER (ilog2(VMEMMAP_OPTIMIZATION_NR_STRUCT_PAGES) + 1) #define __VMEMMAP_OPTIMIZATION_NR_ORDERS \ -- cgit v1.2.3