[v1] mm/migration: rework movable_ops page migration (part 1)

[PATCH v1 06/29] mm/zsmalloc: make PageZsmalloc() sticky until the page is freed

Posted by David Hildenbrand 3 months, 1 week ago

Let the page freeing code handle clearing the page type.

Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Harry Yoo <harry.yoo@oracle.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 mm/zpdesc.h   | 5 -----
 mm/zsmalloc.c | 3 +--
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/mm/zpdesc.h b/mm/zpdesc.h
index 5cb7e3de43952..5763f36039736 100644
--- a/mm/zpdesc.h
+++ b/mm/zpdesc.h
@@ -163,11 +163,6 @@ static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc)
 	__SetPageZsmalloc(zpdesc_page(zpdesc));
 }
 
-static inline void __zpdesc_clear_zsmalloc(struct zpdesc *zpdesc)
-{
-	__ClearPageZsmalloc(zpdesc_page(zpdesc));
-}
-
 static inline struct zone *zpdesc_zone(struct zpdesc *zpdesc)
 {
 	return page_zone(zpdesc_page(zpdesc));
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 7f1431f2be98f..f98747aed4330 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -880,7 +880,7 @@ static void reset_zpdesc(struct zpdesc *zpdesc)
 	ClearPagePrivate(page);
 	zpdesc->zspage = NULL;
 	zpdesc->next = NULL;
-	__ClearPageZsmalloc(page);
+	/* PageZsmalloc is sticky until the page is freed to the buddy. */
 }
 
 static int trylock_zspage(struct zspage *zspage)
@@ -1055,7 +1055,6 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
 		if (!zpdesc) {
 			while (--i >= 0) {
 				zpdesc_dec_zone_page_state(zpdescs[i]);
-				__zpdesc_clear_zsmalloc(zpdescs[i]);
 				free_zpdesc(zpdescs[i]);
 			}
 			cache_free_zspage(pool, zspage);
-- 
2.49.0

Re: [PATCH v1 06/29] mm/zsmalloc: make PageZsmalloc() sticky until the page is freed

Posted by Lorenzo Stoakes 3 months, 1 week ago

On Mon, Jun 30, 2025 at 02:59:47PM +0200, David Hildenbrand wrote:
> Let the page freeing code handle clearing the page type.
>
> Acked-by: Zi Yan <ziy@nvidia.com>
> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
> Acked-by: Harry Yoo <harry.yoo@oracle.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

On basis of sanity of UINT_MAX thing:

Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

> ---
>  mm/zpdesc.h   | 5 -----
>  mm/zsmalloc.c | 3 +--
>  2 files changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/mm/zpdesc.h b/mm/zpdesc.h
> index 5cb7e3de43952..5763f36039736 100644
> --- a/mm/zpdesc.h
> +++ b/mm/zpdesc.h
> @@ -163,11 +163,6 @@ static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc)
>  	__SetPageZsmalloc(zpdesc_page(zpdesc));
>  }
>
> -static inline void __zpdesc_clear_zsmalloc(struct zpdesc *zpdesc)
> -{
> -	__ClearPageZsmalloc(zpdesc_page(zpdesc));
> -}
> -
>  static inline struct zone *zpdesc_zone(struct zpdesc *zpdesc)
>  {
>  	return page_zone(zpdesc_page(zpdesc));
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 7f1431f2be98f..f98747aed4330 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -880,7 +880,7 @@ static void reset_zpdesc(struct zpdesc *zpdesc)
>  	ClearPagePrivate(page);
>  	zpdesc->zspage = NULL;
>  	zpdesc->next = NULL;
> -	__ClearPageZsmalloc(page);
> +	/* PageZsmalloc is sticky until the page is freed to the buddy. */
>  }
>
>  static int trylock_zspage(struct zspage *zspage)
> @@ -1055,7 +1055,6 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
>  		if (!zpdesc) {
>  			while (--i >= 0) {
>  				zpdesc_dec_zone_page_state(zpdescs[i]);

Maybe for consistency put a

/* PageZsmalloc is sticky until the page is freed to the buddy. */

comment here also?

> -				__zpdesc_clear_zsmalloc(zpdescs[i]);
>  				free_zpdesc(zpdescs[i]);
>  			}
>  			cache_free_zspage(pool, zspage);
> --
> 2.49.0
>

Re: [PATCH v1 06/29] mm/zsmalloc: make PageZsmalloc() sticky until the page is freed

Posted by David Hildenbrand 3 months, 1 week ago

On 30.06.25 18:03, Lorenzo Stoakes wrote:
> On Mon, Jun 30, 2025 at 02:59:47PM +0200, David Hildenbrand wrote:
>> Let the page freeing code handle clearing the page type.
>>
>> Acked-by: Zi Yan <ziy@nvidia.com>
>> Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
>> Acked-by: Harry Yoo <harry.yoo@oracle.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> On basis of sanity of UINT_MAX thing:
> 
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
> 
>> ---
>>   mm/zpdesc.h   | 5 -----
>>   mm/zsmalloc.c | 3 +--
>>   2 files changed, 1 insertion(+), 7 deletions(-)
>>
>> diff --git a/mm/zpdesc.h b/mm/zpdesc.h
>> index 5cb7e3de43952..5763f36039736 100644
>> --- a/mm/zpdesc.h
>> +++ b/mm/zpdesc.h
>> @@ -163,11 +163,6 @@ static inline void __zpdesc_set_zsmalloc(struct zpdesc *zpdesc)
>>   	__SetPageZsmalloc(zpdesc_page(zpdesc));
>>   }
>>
>> -static inline void __zpdesc_clear_zsmalloc(struct zpdesc *zpdesc)
>> -{
>> -	__ClearPageZsmalloc(zpdesc_page(zpdesc));
>> -}
>> -
>>   static inline struct zone *zpdesc_zone(struct zpdesc *zpdesc)
>>   {
>>   	return page_zone(zpdesc_page(zpdesc));
>> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
>> index 7f1431f2be98f..f98747aed4330 100644
>> --- a/mm/zsmalloc.c
>> +++ b/mm/zsmalloc.c
>> @@ -880,7 +880,7 @@ static void reset_zpdesc(struct zpdesc *zpdesc)
>>   	ClearPagePrivate(page);
>>   	zpdesc->zspage = NULL;
>>   	zpdesc->next = NULL;
>> -	__ClearPageZsmalloc(page);
>> +	/* PageZsmalloc is sticky until the page is freed to the buddy. */
>>   }
>>
>>   static int trylock_zspage(struct zspage *zspage)
>> @@ -1055,7 +1055,6 @@ static struct zspage *alloc_zspage(struct zs_pool *pool,
>>   		if (!zpdesc) {
>>   			while (--i >= 0) {
>>   				zpdesc_dec_zone_page_state(zpdescs[i]);
> 
> Maybe for consistency put a
> 
> /* PageZsmalloc is sticky until the page is freed to the buddy. */
> 

I'll add that inside free_zpdesc(), before the __free_page().

Thanks!

-- 
Cheers,

David / dhildenb