[PATCH] mm: Remove mlock_count from struct page

[PATCH] mm: Remove mlock_count from struct page

[Matthew Wilcox (Oracle)]

All users now use folio->mlock_count so we can remove this element of
struct page.  Move the useful comments over to struct folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 include/linux/mm_types.h | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d934a3a5b443..34205313a839 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -94,14 +94,6 @@ struct page {
 			union {
 				struct list_head lru;
 
-				/* Or, for the Unevictable "LRU list" slot */
-				struct {
-					/* Always even, to negate PageTail */
-					void *__filler;
-					/* Count page's or folio's mlocks */
-					unsigned int mlock_count;
-				};
-
 				/* Or, free page */
 				struct list_head buddy_list;
 				struct list_head pcp_list;
@@ -391,7 +383,9 @@ struct folio {
 			union {
 				struct list_head lru;
 	/* private: avoid cluttering the output */
+				/* For the Unevictable "LRU list" slot */
 				struct {
+					/* Avoid compound_head */
 					void *__filler;
 	/* public: */
 					unsigned int mlock_count;
-- 
2.47.2

Re: [PATCH] mm: Remove mlock_count from struct page

[David Hildenbrand]

On 03.09.25 21:10, Matthew Wilcox (Oracle) wrote:
> All users now use folio->mlock_count so we can remove this element of
> struct page.  Move the useful comments over to struct folio.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   include/linux/mm_types.h | 10 ++--------
>   1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index d934a3a5b443..34205313a839 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -94,14 +94,6 @@ struct page {
>   			union {
>   				struct list_head lru;
>   
> -				/* Or, for the Unevictable "LRU list" slot */
> -				struct {
> -					/* Always even, to negate PageTail */
> -					void *__filler;
> -					/* Count page's or folio's mlocks */
> -					unsigned int mlock_count;
> -				};
> -
>   				/* Or, free page */
>   				struct list_head buddy_list;
>   				struct list_head pcp_list;
> @@ -391,7 +383,9 @@ struct folio {
>   			union {
>   				struct list_head lru;
>   	/* private: avoid cluttering the output */
> +				/* For the Unevictable "LRU list" slot */
>   				struct {
> +					/* Avoid compound_head */
>   					void *__filler;
>   	/* public: */
>   					unsigned int mlock_count;

mm/mlock.c:      * will call mlock_vma_folio() and raise page's mlock_count:

Should probably fixed up as well.


Documentation/mm/unevictable-lru.rst also seems to talk about pages and 
mlock_count, but that probably needs a bigger rework to only talk about 
folios.

-- 
Cheers

David / dhildenb