The patch titled
Subject: mm: simplify split_page_memcg()
has been added to the -mm mm-unstable branch. Its filename is
mm-simplify-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-simplify-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
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: simplify split_page_memcg()
Date: Fri, 14 Mar 2025 13:36:12 +0000
The last argument to split_page_memcg() is now always 0, so remove it,
effectively reverting commit b8791381d7ed.
Link: https://lkml.kernel.org/r/20250314133617.138071-3-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Acked-by: Zi Yan <ziy@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 4 ++--
mm/memcontrol.c | 15 +++++++--------
mm/page_alloc.c | 4 ++--
3 files changed, 11 insertions(+), 12 deletions(-)
--- a/include/linux/memcontrol.h~mm-simplify-split_page_memcg
+++ a/include/linux/memcontrol.h
@@ -1038,7 +1038,7 @@ static inline void memcg_memory_event_mm
rcu_read_unlock();
}
-void split_page_memcg(struct page *head, int old_order, int new_order);
+void split_page_memcg(struct page *first, unsigned order);
void folio_split_memcg_refs(struct folio *folio, unsigned old_order,
unsigned new_order);
@@ -1461,7 +1461,7 @@ void count_memcg_event_mm(struct mm_stru
{
}
-static inline void split_page_memcg(struct page *head, int old_order, int new_order)
+static inline void split_page_memcg(struct page *first, unsigned order)
{
}
--- a/mm/memcontrol.c~mm-simplify-split_page_memcg
+++ a/mm/memcontrol.c
@@ -3066,22 +3066,21 @@ void __memcg_slab_free_hook(struct kmem_
}
/*
- * Because folio_memcg(head) is not set on tails, set it now.
+ * The objcg is only set on the first page, so transfer it to all the
+ * other pages.
*/
-void split_page_memcg(struct page *head, int old_order, int new_order)
+void split_page_memcg(struct page *first, unsigned order)
{
- struct folio *folio = page_folio(head);
- int i;
- unsigned int old_nr = 1 << old_order;
- unsigned int new_nr = 1 << new_order;
+ struct folio *folio = page_folio(first);
+ unsigned int i, nr = 1 << order;
if (mem_cgroup_disabled() || !folio_memcg_charged(folio))
return;
- for (i = new_nr; i < old_nr; i += new_nr)
+ for (i = 1; i < nr; i++)
folio_page(folio, i)->memcg_data = folio->memcg_data;
- obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1);
+ obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
}
void folio_split_memcg_refs(struct folio *folio, unsigned old_order,
--- a/mm/page_alloc.c~mm-simplify-split_page_memcg
+++ a/mm/page_alloc.c
@@ -2778,7 +2778,7 @@ void split_page(struct page *page, unsig
set_page_refcounted(page + i);
split_page_owner(page, order, 0);
pgalloc_tag_split(page_folio(page), order, 0);
- split_page_memcg(page, order, 0);
+ split_page_memcg(page, order);
}
EXPORT_SYMBOL_GPL(split_page);
@@ -4992,7 +4992,7 @@ static void *make_alloc_exact(unsigned l
split_page_owner(page, order, 0);
pgalloc_tag_split(page_folio(page), order, 0);
- split_page_memcg(page, order, 0);
+ split_page_memcg(page, order);
while (page < --last)
set_page_refcounted(last);
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-decline-to-manipulate-the-refcount-on-a-slab-page.patch
dax-remove-access-to-page-index.patch
dax-use-folios-more-widely-within-dax.patch
fs-convert-block_commit_write-to-take-a-folio.patch
fs-remove-page_file_mapping.patch
fs-remove-folio_file_mapping.patch
mm-assert-the-folio-is-locked-in-folio_start_writeback.patch
hugetlb-convert-hugetlb_vma_maps_page-to-hugetlb_vma_maps_pfn.patch
hugetlb-convert-adjust_range_hwpoison-to-take-a-folio.patch
mm-convert-lru_add_page_tail-to-lru_add_split_folio.patch
mm-separate-folio_split_memcg_refs-from-split_page_memcg.patch
mm-simplify-split_page_memcg.patch
mm-remove-references-to-folio-in-split_page_memcg.patch
mm-simplify-folio_memcg_charged.patch
mm-remove-references-to-folio-in-__memcg_kmem_uncharge_page.patch
ocfs2-use-memcpy_to_folio-in-ocfs2_symlink_get_block.patch
ocfs2-remove-reference-to-bh-b_page.patch
