[PATCH v3 03/11] mm/sparse-vmemmap: open-code init_compound_tail()
From: Muchun Song <hidden>
Date: 2026-09-11 05:03:42
Also in:
linux-doc, linux-mm, lkml
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
init_compound_tail() is only used by vmemmap_shared_tail_page(), where the shared tail page setup intentionally passes NULL as the compound head. Keeping this helper in mm/internal.h exposes that special case to the rest of the MM code and can make the NULL head argument look generally valid. Open-code the initialization at the only call site so the special-case use stays local to sparse vmemmap optimization. No functional change intended. Signed-off-by: Muchun Song <redacted> Acked-by: Qi Zheng <qi.zheng@linux.dev> Acked-by: David Hildenbrand (Arm) <david@kernel.org> --- v3: - Collect Acked-by from David Hildenbrand v2: - Collect Acked-by from Qi Zheng --- mm/internal.h | 9 --------- mm/sparse-vmemmap.c | 5 ++++- 2 files changed, 4 insertions(+), 10 deletions(-)
diff --git a/mm/internal.h b/mm/internal.h
index da14c56fb24e..0dca33db068f 100644
--- a/mm/internal.h
+++ b/mm/internal.h@@ -786,15 +786,6 @@ static inline void prep_compound_tail(struct page *tail, VM_WARN_ON_ONCE(tail->private); } -static inline void init_compound_tail(struct page *tail, - const struct page *head, unsigned int order, struct zone *zone) -{ - atomic_set(&tail->_mapcount, -1); - set_page_node(tail, zone_to_nid(zone)); - set_page_zone(tail, zone_idx(zone)); - prep_compound_tail(tail, head, order); -} - #if defined CONFIG_COMPACTION || defined CONFIG_CMA /*
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 7388a5b5cce3..861e09b2b096 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c@@ -189,7 +189,10 @@ struct page __ref *vmemmap_shared_tail_page(unsigned int order, struct zone *zon for (int i = 0; i < PAGE_SIZE / sizeof(struct page); i++) { page = (struct page *)addr + i; mm_zero_struct_page(page); - init_compound_tail(page, NULL, order, zone); + atomic_set(&page->_mapcount, -1); + set_page_node(page, zone_to_nid(zone)); + set_page_zone(page, zone_idx(zone)); + prep_compound_tail(page, NULL, order); } page = virt_to_page(addr);
--
2.54.0