[PATCH] ksm: update comments and docs to reference folio->mapping

[PATCH] ksm: update comments and docs to reference folio->mapping

[Hongfu Li]

From: Hongfu Li <lihongfu@kylinos.cn>

The KSM code already stores and checks the stable node key via
folio->mapping, but the comment in ksm_get_folio() and the reverse
mapping documentation in ksm.rst still refer to page->mapping.

This is a pure wording update to match the folio-based implementation.
No functional change is intended.

Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
---
 Documentation/mm/ksm.rst                    | 4 ++--
 Documentation/translations/zh_CN/mm/ksm.rst | 4 ++--
 mm/ksm.c                                    | 7 +++----
 3 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/Documentation/mm/ksm.rst b/Documentation/mm/ksm.rst
index 2806e3e4a10e..2b4f72f1f953 100644
--- a/Documentation/mm/ksm.rst
+++ b/Documentation/mm/ksm.rst
@@ -24,13 +24,13 @@ tree.
 
 If a KSM page is shared between less than ``max_page_sharing`` VMAs,
 the node of the stable tree that represents such KSM page points to a
-list of struct ksm_rmap_item and the ``page->mapping`` of the
+list of struct ksm_rmap_item and the ``folio->mapping`` of the
 KSM page points to the stable tree node.
 
 When the sharing passes this threshold, KSM adds a second dimension to
 the stable tree. The tree node becomes a "chain" that links one or
 more "dups". Each "dup" keeps reverse mapping information for a KSM
-page with ``page->mapping`` pointing to that "dup".
+page with ``folio->mapping`` pointing to that "dup".
 
 Every "chain" and all "dups" linked into a "chain" enforce the
 invariant that they represent the same write protected memory content,
diff --git a/Documentation/translations/zh_CN/mm/ksm.rst b/Documentation/translations/zh_CN/mm/ksm.rst
index f0f458753d0c..822c7a289671 100644
--- a/Documentation/translations/zh_CN/mm/ksm.rst
+++ b/Documentation/translations/zh_CN/mm/ksm.rst
@@ -31,10 +31,10 @@ KSM维护着稳定树中的KSM页的逆映射信息。
 
 当KSM页面的共享数小于 ``max_page_sharing`` 的虚拟内存区域(VMAs)时，则代表了
 KSM页的稳定树其中的节点指向了一个ksm_rmap_item结构体类型的列表。同时，这个KSM页
-的 ``page->mapping`` 指向了该稳定树节点。
+的 ``folio->mapping`` 指向了该稳定树节点。
 
 如果共享数超过了阈值，KSM将给稳定树添加第二个维度。稳定树就变成链接一个或多
-个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``page->mapping``
+个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``folio->mapping``
 指向该"副本"。
 
 每个链以及链接到该链中的所有"副本"强制不变的是，它们代表了相同的写保护内存
diff --git a/mm/ksm.c b/mm/ksm.c
index ab1fc59424e8..4bde9fd8d44e 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -959,10 +959,9 @@ enum ksm_get_folio_flags {
  * seconds or even minutes: much too unresponsive.  So instead we use a
  * "keyhole reference": access to the ksm page from the stable node peeps
  * out through its keyhole to see if that page still holds the right key,
- * pointing back to this stable node.  This relies on freeing a PageAnon
- * page to reset its page->mapping to NULL, and relies on no other use of
- * a page to put something that might look like our key in page->mapping.
- * is on its way to being freed; but it is an anomaly to bear in mind.
+ * pointing back to this stable node.  This relies on freeing an anon
+ * folio to reset its mapping to NULL, and relies on no other use of a
+ * folio to put something that might look like our key in its mapping.
  */
 static struct folio *ksm_get_folio(struct ksm_stable_node *stable_node,
 				 enum ksm_get_folio_flags flags)
-- 
2.54.0

Re: [PATCH] ksm: update comments and docs to reference folio->mapping

[David Hildenbrand (Arm)]

On 8/5/26 12:59, Hongfu Li wrote:
> From: Hongfu Li <lihongfu@kylinos.cn>
> 
> The KSM code already stores and checks the stable node key via
> folio->mapping, but the comment in ksm_get_folio() and the reverse
> mapping documentation in ksm.rst still refer to page->mapping.
> 
> This is a pure wording update to match the folio-based implementation.
> No functional change is intended.
> 
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> ---

No idea about the Chinese stuff, but looks correct.

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David

Re: [PATCH] ksm: update comments and docs to reference folio->mapping

[xu.xin16]

> The KSM code already stores and checks the stable node key via
> folio->mapping, but the comment in ksm_get_folio() and the reverse
> mapping documentation in ksm.rst still refer to page->mapping.
>
> This is a pure wording update to match the folio-based implementation.
> No functional change is intended.
> 
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> ---
> Documentation/mm/ksm.rst                    | 4 ++--
> Documentation/translations/zh_CN/mm/ksm.rst | 4 ++--
> mm/ksm.c                                    | 7 +++----
> 3 files changed, 7 insertions(+), 8 deletions(-)

Reviewed-by: Xu Xin <xu.xin16@zte.com.cn>

Re: [PATCH] ksm: update comments and docs to reference folio->mapping

[Dongliang Mu]

On 8/5/26 6:59 PM, Hongfu Li wrote:
> From: Hongfu Li <lihongfu@kylinos.cn>
>
> The KSM code already stores and checks the stable node key via
> folio->mapping, but the comment in ksm_get_folio() and the reverse
> mapping documentation in ksm.rst still refer to page->mapping.
>
> This is a pure wording update to match the folio-based implementation.
> No functional change is intended.
>
> Signed-off-by: Hongfu Li <lihongfu@kylinos.cn>
> ---
>   Documentation/mm/ksm.rst                    | 4 ++--
>   Documentation/translations/zh_CN/mm/ksm.rst | 4 ++--
>   mm/ksm.c                                    | 7 +++----
>   3 files changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/mm/ksm.rst b/Documentation/mm/ksm.rst
> index 2806e3e4a10e..2b4f72f1f953 100644
> --- a/Documentation/mm/ksm.rst
> +++ b/Documentation/mm/ksm.rst
> @@ -24,13 +24,13 @@ tree.
>   
>   If a KSM page is shared between less than ``max_page_sharing`` VMAs,
>   the node of the stable tree that represents such KSM page points to a
> -list of struct ksm_rmap_item and the ``page->mapping`` of the
> +list of struct ksm_rmap_item and the ``folio->mapping`` of the
>   KSM page points to the stable tree node.
>   
>   When the sharing passes this threshold, KSM adds a second dimension to
>   the stable tree. The tree node becomes a "chain" that links one or
>   more "dups". Each "dup" keeps reverse mapping information for a KSM
> -page with ``page->mapping`` pointing to that "dup".
> +page with ``folio->mapping`` pointing to that "dup".
>   
>   Every "chain" and all "dups" linked into a "chain" enforce the
>   invariant that they represent the same write protected memory content,
> diff --git a/Documentation/translations/zh_CN/mm/ksm.rst b/Documentation/translations/zh_CN/mm/ksm.rst
> index f0f458753d0c..822c7a289671 100644
> --- a/Documentation/translations/zh_CN/mm/ksm.rst
> +++ b/Documentation/translations/zh_CN/mm/ksm.rst
> @@ -31,10 +31,10 @@ KSM维护着稳定树中的KSM页的逆映射信息。
>   
>   当KSM页面的共享数小于 ``max_page_sharing`` 的虚拟内存区域(VMAs)时，则代表了
>   KSM页的稳定树其中的节点指向了一个ksm_rmap_item结构体类型的列表。同时，这个KSM页
> -的 ``page->mapping`` 指向了该稳定树节点。
> +的 ``folio->mapping`` 指向了该稳定树节点。
>   
>   如果共享数超过了阈值，KSM将给稳定树添加第二个维度。稳定树就变成链接一个或多
> -个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``page->mapping``
> +个稳定树"副本"的"链"。每个副本都保留KSM页的逆映射信息，其中 ``folio->mapping``
>   指向该"副本"。

The Chinese translation looks good to me.

Reviewed-by: Dongliang Mu <dzm91@hust.edu.cn>

>   
>   每个链以及链接到该链中的所有"副本"强制不变的是，它们代表了相同的写保护内存
> diff --git a/mm/ksm.c b/mm/ksm.c
> index ab1fc59424e8..4bde9fd8d44e 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -959,10 +959,9 @@ enum ksm_get_folio_flags {
>    * seconds or even minutes: much too unresponsive.  So instead we use a
>    * "keyhole reference": access to the ksm page from the stable node peeps
>    * out through its keyhole to see if that page still holds the right key,
> - * pointing back to this stable node.  This relies on freeing a PageAnon
> - * page to reset its page->mapping to NULL, and relies on no other use of
> - * a page to put something that might look like our key in page->mapping.
> - * is on its way to being freed; but it is an anomaly to bear in mind.
> + * pointing back to this stable node.  This relies on freeing an anon
> + * folio to reset its mapping to NULL, and relies on no other use of a
> + * folio to put something that might look like our key in its mapping.
>    */
>   static struct folio *ksm_get_folio(struct ksm_stable_node *stable_node,
>   				 enum ksm_get_folio_flags flags)