[PATCH v5 5/8] mm: memcg: make memcg huge page split support any order split.

Zi Yan
2024-02-26T20:56:23Z

From: Zi Yan <ziy@nvidia.com>

It sets memcg information for the pages after the split. A new parameter
new_order is added to tell the order of subpages in the new page, always 0
for now. It prepares for upcoming changes to support split huge page to
any lower order.

Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
include/linux/memcontrol.h | 4 ++--
mm/huge_memory.c | 2 +-
mm/memcontrol.c | 11 ++++++-----
mm/page_alloc.c | 4 ++--
4 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 173bbb53c1ec..9a2dea92be0e 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1163,7 +1163,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
rcu_read_unlock();
}

-void split_page_memcg(struct page *head, int order);
+void split_page_memcg(struct page *head, int old_order, int new_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_struct *mm, enum vm_event_item idx)
{
}

-static inline void split_page_memcg(struct page *head, int order)
+static inline void split_page_memcg(struct page *head, int old_order, int new_order)
{
}

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 2b95dbc95fae..5d4b7c17b9bc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2894,7 +2894,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
unsigned int nr = 1 << order;

/* complete memcg works before add pages to LRU */
- split_page_memcg(head, order);
+ split_page_memcg(head, order, 0);

if (folio_test_anon(folio) && folio_test_swapcache(folio)) {
offset = swp_offset(folio->swap);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1a09f0e77c44..669bc8de3780 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3608,23 +3608,24 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
/*
* Because page_memcg(head) is not set on tails, set it now.
*/
-void split_page_memcg(struct page *head, int order)
+void split_page_memcg(struct page *head, int old_order, int new_order)
{
struct folio *folio = page_folio(head);
struct mem_cgroup *memcg = folio_memcg(folio);
int i;
- unsigned int nr = 1 << order;
+ unsigned int old_nr = 1 << old_order;
+ unsigned int new_nr = 1 << new_order;

if (mem_cgroup_disabled() || !memcg)
return;

- for (i = 1; i < nr; i++)
+ for (i = new_nr; i < old_nr; i += new_nr)
folio_page(folio, i)->memcg_data = folio->memcg_data;

if (folio_memcg_kmem(folio))
- obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
+ obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1);
else
- css_get_many(&memcg->css, nr - 1);
+ css_get_many(&memcg->css, old_nr / new_nr - 1);
}

#ifdef CONFIG_SWAP
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index eae77e76a671..c31a468fe317 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2653,7 +2653,7 @@ void split_page(struct page *page, unsigned int order)
for (i = 1; i < (1 << order); i++)
set_page_refcounted(page + i);
split_page_owner(page, order);
- split_page_memcg(page, order);
+ split_page_memcg(page, order, 0);
}
EXPORT_SYMBOL_GPL(split_page);

@@ -4840,7 +4840,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
struct page *last = page + nr;

split_page_owner(page, order);
- split_page_memcg(page, order);
+ split_page_memcg(page, order, 0);
while (page < --last)
set_page_refcounted(last);

--
2.43.0