Re: [PATCH v4 07/34] mm: Convert ptlock_alloc() to use ptdescs

On Mon, Jun 12, 2023 at 02:03:56PM -0700, Vishal Moola (Oracle) wrote:
> This removes some direct accesses to struct page, working towards
> splitting out struct ptdesc from struct page.
> 
> Signed-off-by: Vishal Moola (Oracle) <[email protected]>

Acked-by: Mike Rapoport (IBM) <[email protected]>

> ---
>  include/linux/mm.h | 6 +++---
>  mm/memory.c        | 4 ++--
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 088b7664f897..e6f1be2a405e 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2825,7 +2825,7 @@ static inline void pagetable_clear(void *x)
>  #if USE_SPLIT_PTE_PTLOCKS
>  #if ALLOC_SPLIT_PTLOCKS
>  void __init ptlock_cache_init(void);
> -extern bool ptlock_alloc(struct page *page);
> +bool ptlock_alloc(struct ptdesc *ptdesc);
>  extern void ptlock_free(struct page *page);
>  
>  static inline spinlock_t *ptlock_ptr(struct page *page)
> @@ -2837,7 +2837,7 @@ static inline void ptlock_cache_init(void)
>  {
>  }
>  
> -static inline bool ptlock_alloc(struct page *page)
> +static inline bool ptlock_alloc(struct ptdesc *ptdesc)
>  {
>  	return true;
>  }
> @@ -2867,7 +2867,7 @@ static inline bool ptlock_init(struct page *page)
>  	 * slab code uses page->slab_cache, which share storage with page->ptl.
>  	 */
>  	VM_BUG_ON_PAGE(*(unsigned long *)&page->ptl, page);
> -	if (!ptlock_alloc(page))
> +	if (!ptlock_alloc(page_ptdesc(page)))
>  		return false;
>  	spin_lock_init(ptlock_ptr(page));
>  	return true;
> diff --git a/mm/memory.c b/mm/memory.c
> index 80ce9dda2779..ba9579117686 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5934,14 +5934,14 @@ void __init ptlock_cache_init(void)
>  			SLAB_PANIC, NULL);
>  }
>  
> -bool ptlock_alloc(struct page *page)
> +bool ptlock_alloc(struct ptdesc *ptdesc)
>  {
>  	spinlock_t *ptl;
>  
>  	ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
>  	if (!ptl)
>  		return false;
> -	page->ptl = ptl;
> +	ptdesc->ptl = ptl;
>  	return true;
>  }
>  
> -- 
> 2.40.1
> 
> 

-- 
Sincerely yours,
Mike.