The patch titled Subject: mm/memcg: use order instead of nr in split_page_memcg() has been added to the -mm mm-unstable branch. Its filename is mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Zi Yan <ziy@xxxxxxxxxx> Subject: mm/memcg: use order instead of nr in split_page_memcg() Date: Mon, 26 Feb 2024 15:55:29 -0500 We do not have non power of two pages, using nr is error prone if nr is not power-of-two. Use page order instead. Link: https://lkml.kernel.org/r/20240226205534.1603748-4-zi.yan@xxxxxxxx Signed-off-by: Zi Yan <ziy@xxxxxxxxxx> Acked-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Cc: Michal Koutny <mkoutny@xxxxxxxx> Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx> Cc: Ryan Roberts <ryan.roberts@xxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Cc: Yu Zhao <yuzhao@xxxxxxxxxx> Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/memcontrol.h | 4 ++-- mm/huge_memory.c | 5 +++-- mm/memcontrol.c | 3 ++- mm/page_alloc.c | 4 ++-- 4 files changed, 9 insertions(+), 7 deletions(-) --- a/include/linux/memcontrol.h~mm-memcg-use-order-instead-of-nr-in-split_page_memcg +++ a/include/linux/memcontrol.h @@ -1163,7 +1163,7 @@ static inline void memcg_memory_event_mm rcu_read_unlock(); } -void split_page_memcg(struct page *head, unsigned int nr); +void split_page_memcg(struct page *head, int order); unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order, gfp_t gfp_mask, @@ -1621,7 +1621,7 @@ void count_memcg_event_mm(struct mm_stru { } -static inline void split_page_memcg(struct page *head, unsigned int nr) +static inline void split_page_memcg(struct page *head, int order) { } --- a/mm/huge_memory.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg +++ a/mm/huge_memory.c @@ -2889,11 +2889,12 @@ static void __split_huge_page(struct pag struct lruvec *lruvec; struct address_space *swap_cache = NULL; unsigned long offset = 0; - unsigned int nr = thp_nr_pages(head); int i, nr_dropped = 0; + int order = folio_order(folio); + unsigned int nr = 1 << order; /* complete memcg works before add pages to LRU */ - split_page_memcg(head, nr); + split_page_memcg(head, order); if (folio_test_anon(folio) && folio_test_swapcache(folio)) { offset = swp_offset(folio->swap); --- a/mm/memcontrol.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg +++ a/mm/memcontrol.c @@ -3606,11 +3606,12 @@ void obj_cgroup_uncharge(struct obj_cgro /* * Because page_memcg(head) is not set on tails, set it now. */ -void split_page_memcg(struct page *head, unsigned int nr) +void split_page_memcg(struct page *head, int order) { struct folio *folio = page_folio(head); struct mem_cgroup *memcg = folio_memcg(folio); int i; + unsigned int nr = 1 << order; if (mem_cgroup_disabled() || !memcg) return; --- a/mm/page_alloc.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg +++ a/mm/page_alloc.c @@ -2617,7 +2617,7 @@ void split_page(struct page *page, unsig for (i = 1; i < (1 << order); i++) set_page_refcounted(page + i); split_page_owner(page, 1 << order); - split_page_memcg(page, 1 << order); + split_page_memcg(page, order); } EXPORT_SYMBOL_GPL(split_page); @@ -4804,7 +4804,7 @@ static void *make_alloc_exact(unsigned l struct page *last = page + nr; split_page_owner(page, 1 << order); - split_page_memcg(page, 1 << order); + split_page_memcg(page, order); while (page < --last) set_page_refcounted(last); _ Patches currently in -mm which might be from ziy@xxxxxxxxxx are mm-huge_memory-only-split-pmd-mapping-when-necessary-in-unmap_folio.patch mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch mm-page_owner-use-order-instead-of-nr-in-split_page_owner.patch mm-memcg-make-memcg-huge-page-split-support-any-order-split.patch mm-page_owner-add-support-for-splitting-to-any-order-in-split-page_owner.patch mm-thp-split-huge-page-to-any-lower-order-pages.patch mm-huge_memory-enable-debugfs-to-split-huge-pages-to-any-order.patch