[PATCH v2 4/7] mm: page_owner: add support for splitting to any order in split page_owner.

From: Zi Yan
Date: Tue Mar 28 2023 - 21:17:53 EST


From: Zi Yan <ziy@xxxxxxxxxx>

It adds a new_order parameter to set new page order in page owner.
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 | 2 +-
mm/page_alloc.c | 4 ++--
mm/page_owner.c | 11 ++++++-----
4 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index d7878523adfc..a784ba69f67f 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -11,7 +11,7 @@ extern struct page_ext_operations page_owner_ops;
extern void __reset_page_owner(struct page *page, unsigned short order);
extern void __set_page_owner(struct page *page,
unsigned short order, gfp_t gfp_mask);
-extern void __split_page_owner(struct page *page, int order);
+extern void __split_page_owner(struct page *page, int old_order, int new_order);
extern void __folio_copy_owner(struct folio *newfolio, struct folio *old);
extern void __set_page_owner_migrate_reason(struct page *page, int reason);
extern void __dump_page_owner(const struct page *page);
@@ -31,10 +31,10 @@ 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, int order)
+static inline void split_page_owner(struct page *page, int old_order, int new_order)
{
if (static_branch_unlikely(&page_owner_inited))
- __split_page_owner(page, order);
+ __split_page_owner(page, old_order, new_order);
}
static inline void folio_copy_owner(struct folio *newfolio, struct folio *old)
{
@@ -56,11 +56,11 @@ static inline void reset_page_owner(struct page *page, unsigned short order)
{
}
static inline void set_page_owner(struct page *page,
- unsigned int order, gfp_t gfp_mask)
+ unsigned short order, gfp_t gfp_mask)
{
}
static inline void split_page_owner(struct page *page,
- int order)
+ int old_order, int new_order)
{
}
static inline void folio_copy_owner(struct folio *newfolio, struct folio *folio)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 106cde74d933..f8a8a72b207d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2557,7 +2557,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
unlock_page_lruvec(lruvec);
/* Caller disabled irqs, so they are still disabled here */

- split_page_owner(head, order);
+ 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 ef559795525b..4845ff6c4223 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2780,7 +2780,7 @@ 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_owner(page, order, 0);
split_page_memcg(page, order, 0);
}
EXPORT_SYMBOL_GPL(split_page);
@@ -4996,7 +4996,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
struct page *page = virt_to_page((void *)addr);
struct page *last = page + nr;

- split_page_owner(page, order);
+ split_page_owner(page, order, 0);
split_page_memcg(page, order, 0);
while (page < --last)
set_page_refcounted(last);
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 64233b5b09d5..347861fe9c50 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -211,20 +211,21 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
page_ext_put(page_ext);
}

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

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;
}
page_ext_put(page_ext);
}
--
2.39.2