[PATCH 4/7] mm: page_owner: add support for splitting to any order in split page_owner.

From: Zi Yan
Date: Thu Nov 19 2020 - 11:06:58 EST


From: Zi Yan <ziy@xxxxxxxxxx>

It adds a new_order parameter to set new page order in page owner and
uses old_order instead of nr to make the parameters look consistent.
It prepares for upcoming changes to support split huge page to any
lower order.

Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
---
include/linux/page_owner.h | 10 ++++++----
mm/huge_memory.c | 3 ++-
mm/page_alloc.c | 2 +-
mm/page_owner.c | 13 +++++++------
4 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 3468794f83d2..9caaed51403c 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -11,7 +11,8 @@ extern struct page_ext_operations page_owner_ops;
extern void __reset_page_owner(struct page *page, unsigned int order);
extern void __set_page_owner(struct page *page,
unsigned int order, gfp_t gfp_mask);
-extern void __split_page_owner(struct page *page, unsigned int nr);
+extern void __split_page_owner(struct page *page, unsigned int old_order,
+ unsigned int new_order);
extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
extern void __set_page_owner_migrate_reason(struct page *page, int reason);
extern void __dump_page_owner(struct page *page);
@@ -31,10 +32,11 @@ static inline void set_page_owner(struct page *page,
__set_page_owner(page, order, gfp_mask);
}

-static inline void split_page_owner(struct page *page, unsigned int nr)
+static inline void split_page_owner(struct page *page, unsigned int old_order,
+ unsigned int new_order)
{
if (static_branch_unlikely(&page_owner_inited))
- __split_page_owner(page, nr);
+ __split_page_owner(page, old_order, new_order);
}
static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
{
@@ -60,7 +62,7 @@ static inline void set_page_owner(struct page *page,
{
}
static inline void split_page_owner(struct page *page,
- unsigned int order)
+ unsigned int old_order, unsigned int new_order)
{
}
static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d7ab5cac5851..aae7405a0989 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2422,6 +2422,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
struct lruvec *lruvec;
struct address_space *swap_cache = NULL;
unsigned long offset = 0;
+ unsigned int order = thp_order(head);
unsigned int nr = thp_nr_pages(head);
int i;

@@ -2458,7 +2459,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,

ClearPageCompound(head);

- split_page_owner(head, nr);
+ split_page_owner(head, order, 0);

/* See comment in __split_huge_page_tail() */
if (PageAnon(head)) {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 63d8d8b72c10..414f26950190 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3297,7 +3297,7 @@ 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, 1 << order);
+ split_page_owner(page, order, 0);
}
EXPORT_SYMBOL_GPL(split_page);

diff --git a/mm/page_owner.c b/mm/page_owner.c
index b735a8eafcdb..00a679a1230b 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -204,19 +204,20 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
page_owner->last_migrate_reason = reason;
}

-void __split_page_owner(struct page *page, unsigned int nr)
+void __split_page_owner(struct page *page, unsigned int old_order,
+ unsigned int new_order)
{
- int i;
- struct page_ext *page_ext = lookup_page_ext(page);
+ int i, old_nr = 1 << old_order, new_nr = 1 << new_order;
+ struct page_ext *page_ext;
struct page_owner *page_owner;

if (unlikely(!page_ext))
return;

- for (i = 0; i < nr; i++) {
+ for (i = 0; i < old_nr; i += new_nr) {
+ page_ext = lookup_page_ext(page + i);
page_owner = get_page_owner(page_ext);
- page_owner->order = 0;
- page_ext = page_ext_next(page_ext);
+ page_owner->order = new_order;
}
}

--
2.28.0