2023-03-21 00:49:01

by Zi Yan

[permalink] [raw]
Subject: [PATCH 2/5] mm: page_owner: add support for splitting to any order in split page_owner.

From: Zi Yan <[email protected]>

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 <[email protected]>
---
include/linux/page_owner.h | 12 +++++++-----
mm/huge_memory.c | 3 ++-
mm/page_alloc.c | 6 +++---
mm/page_owner.c | 11 ++++++-----
4 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 119a0c9d2a8b..67d98de3d5a8 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 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, unsigned int nr);
+extern void __split_page_owner(struct page *page, unsigned short old_order,
+ unsigned short 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 +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 short old_order,
+ unsigned short 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 folio_copy_owner(struct folio *newfolio, struct folio *old)
{
@@ -56,11 +58,11 @@ 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,
- unsigned short order)
+ unsigned short old_order, unsigned short 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 30e3e300c42e..710189885402 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2511,6 +2511,7 @@ 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;

@@ -2556,7 +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, 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 59c2b6696698..ec85562865fb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3530,7 +3530,7 @@ 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);
split_page_memcg(page, 1 << order, 1);
}
EXPORT_SYMBOL_GPL(split_page);
@@ -5746,8 +5746,8 @@ 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, 1 << order);
- split_page_memcg(page, 1 << order);
+ split_page_owner(page, 1 << order, 1);
+ split_page_memcg(page, 1 << order, 1);
while (page < --last)
set_page_refcounted(last);

diff --git a/mm/page_owner.c b/mm/page_owner.c
index 31169b3e7f06..33d1b6efe6a6 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -211,19 +211,20 @@ void __set_page_owner_migrate_reason(struct page *page, int reason)
page_ext_put(page_ext);
}

-void __split_page_owner(struct page *page, unsigned int nr)
+void __split_page_owner(struct page *page, unsigned short old_order,
+ unsigned short new_order)
{
- int i;
+ int i, old_nr = 1 << old_order, new_nr = 1 << new_order;
struct page_ext *page_ext = page_ext_get(page);
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;
}
page_ext_put(page_ext);
}
--
2.39.2



2023-03-24 15:19:01

by Michal Koutný

[permalink] [raw]
Subject: Re: [PATCH 2/5] mm: page_owner: add support for splitting to any order in split page_owner.

Hello.

On Mon, Mar 20, 2023 at 08:48:26PM -0400, Zi Yan <[email protected]> wrote:
> @@ -5746,8 +5746,8 @@ 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, 1 << order);
> - split_page_memcg(page, 1 << order);
> + split_page_owner(page, 1 << order, 1);
> + split_page_memcg(page, 1 << order, 1);

I think here should be

> + split_page_owner(page, order, 0);
> + split_page_memcg(page, 1 << order, 1);

because I was wondering why split_page_memcg() doesn't use orders too?
(E.g. it wouldn't work well if nr % new_new != 0).

Thanks,
Michal


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2023-03-24 15:23:51

by Zi Yan

[permalink] [raw]
Subject: Re: [PATCH 2/5] mm: page_owner: add support for splitting to any order in split page_owner.

On 24 Mar 2023, at 11:17, Michal Koutný wrote:

> Hello.
>
> On Mon, Mar 20, 2023 at 08:48:26PM -0400, Zi Yan <[email protected]> wrote:
>> @@ -5746,8 +5746,8 @@ 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, 1 << order);
>> - split_page_memcg(page, 1 << order);
>> + split_page_owner(page, 1 << order, 1);
>> + split_page_memcg(page, 1 << order, 1);
>
> I think here should be
>
>> + split_page_owner(page, order, 0);
>> + split_page_memcg(page, 1 << order, 1);
>
> because I was wondering why split_page_memcg() doesn't use orders too?
> (E.g. it wouldn't work well if nr % new_new != 0).

Thanks. Good point. I will make both use orders instead in next version.


--
Best Regards,
Yan, Zi


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