From: Kiryl Shutsemau Date: Fri, 27 Feb 2026 19:42:40 +0000 (+0000) Subject: mm: change the interface of prep_compound_tail() X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f0369fb13619569ba8564ce8d4fc9d385bbee8a2;p=thirdparty%2Fkernel%2Flinux.git mm: change the interface of prep_compound_tail() Instead of passing down the head page and tail page index, pass the tail and head pages directly, as well as the order of the compound page. This is a preparation for changing how the head position is encoded in the tail page. Link: https://lkml.kernel.org/r/20260227194302.274384-3-kas@kernel.org Signed-off-by: Kiryl Shutsemau Reviewed-by: Muchun Song Reviewed-by: Zi Yan Acked-by: David Hildenbrand (arm) Reviewed-by: Vlastimil Babka Cc: Albert Ou Cc: Alexandre Ghiti Cc: Baoquan He Cc: Christoph Lameter Cc: David Rientjes Cc: Frank van der Linden Cc: Harry Yoo Cc: Huacai Chen Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lorenzo Stoakes Cc: Matthew Wilcox (Oracle) Cc: Michal Hocko Cc: Mike Rapoport Cc: Oscar Salvador Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Roman Gushchin Cc: Usama Arif Cc: WANG Xuerui Signed-off-by: Andrew Morton --- diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 415e9f2ef616b..7729a4a28b443 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -870,9 +870,10 @@ static inline bool folio_test_large(const struct folio *folio) return folio_test_head(folio); } -static __always_inline void set_compound_head(struct page *page, struct page *head) +static __always_inline void set_compound_head(struct page *tail, + const struct page *head, unsigned int order) { - WRITE_ONCE(page->compound_head, (unsigned long)head + 1); + WRITE_ONCE(tail->compound_head, (unsigned long)head + 1); } static __always_inline void clear_compound_head(struct page *page) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 327eaa4074d39..1d41fa3dd43ef 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3168,6 +3168,7 @@ found: /* Initialize [start_page:end_page_number] tail struct pages of a hugepage */ static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio, + struct hstate *h, unsigned long start_page_number, unsigned long end_page_number) { @@ -3176,6 +3177,7 @@ static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio, struct page *page = folio_page(folio, start_page_number); unsigned long head_pfn = folio_pfn(folio); unsigned long pfn, end_pfn = head_pfn + end_page_number; + unsigned int order = huge_page_order(h); /* * As we marked all tail pages with memblock_reserved_mark_noinit(), @@ -3183,7 +3185,7 @@ static void __init hugetlb_folio_init_tail_vmemmap(struct folio *folio, */ for (pfn = head_pfn + start_page_number; pfn < end_pfn; page++, pfn++) { __init_single_page(page, pfn, zone, nid); - prep_compound_tail((struct page *)folio, pfn - head_pfn); + prep_compound_tail(page, &folio->page, order); set_page_count(page, 0); } } @@ -3203,7 +3205,7 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio, __folio_set_head(folio); ret = folio_ref_freeze(folio, 1); VM_BUG_ON(!ret); - hugetlb_folio_init_tail_vmemmap(folio, 1, nr_pages); + hugetlb_folio_init_tail_vmemmap(folio, h, 1, nr_pages); prep_compound_head(&folio->page, huge_page_order(h)); } @@ -3260,7 +3262,7 @@ static void __init prep_and_add_bootmem_folios(struct hstate *h, * time as this is early in boot and there should * be no contention. */ - hugetlb_folio_init_tail_vmemmap(folio, + hugetlb_folio_init_tail_vmemmap(folio, h, HUGETLB_VMEMMAP_RESERVE_PAGES, pages_per_huge_page(h)); } diff --git a/mm/internal.h b/mm/internal.h index 2daa6a744172e..9cfbd8e419145 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -897,13 +897,12 @@ static inline void prep_compound_head(struct page *page, unsigned int order) INIT_LIST_HEAD(&folio->_deferred_list); } -static inline void prep_compound_tail(struct page *head, int tail_idx) +static inline void prep_compound_tail(struct page *tail, + const struct page *head, unsigned int order) { - struct page *p = head + tail_idx; - - p->mapping = TAIL_MAPPING; - set_compound_head(p, head); - set_page_private(p, 0); + tail->mapping = TAIL_MAPPING; + set_compound_head(tail, head, order); + set_page_private(tail, 0); } void post_alloc_hook(struct page *page, unsigned int order, gfp_t gfp_flags); diff --git a/mm/mm_init.c b/mm/mm_init.c index f903747ca854d..5b261f86ba6f3 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1110,7 +1110,7 @@ static void __ref memmap_init_compound(struct page *head, struct page *page = pfn_to_page(pfn); __init_zone_device_page(page, pfn, zone_idx, nid, pgmap); - prep_compound_tail(head, pfn - head_pfn); + prep_compound_tail(page, head, order); set_page_count(page, 0); } prep_compound_head(head, order); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 74b603872f346..11f9a0525a3a9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -744,7 +744,7 @@ void prep_compound_page(struct page *page, unsigned int order) __SetPageHead(page); for (i = 1; i < nr_pages; i++) - prep_compound_tail(page, i); + prep_compound_tail(page + i, page, order); prep_compound_head(page, order); }