Re: [PATCH 3/8] mm/ksm: convert process iterator to for_each_process_rcu

[Michal Hocko <mhocko@suse.com>]

On Fri 04-09-26 16:29:55, Ye Liu wrote:
> From: Ye Liu <liuye@kylinos.cn>
> 
> Replace the manual rcu_read_lock()/rcu_read_unlock() pair combined
> with for_each_process() loop in mm/ksm.c with for_each_process_rcu().
> 
> No functional change.
> 
> Signed-off-by: Ye Liu <liuye@kylinos.cn>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/ksm.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/mm/ksm.c b/mm/ksm.c
> index 49d48d1e0998..fa5e4c47fb1b 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -3280,8 +3280,7 @@ void collect_procs_ksm(const struct folio *folio, const struct page *page,
>  		struct anon_vma *av = rmap_item->anon_vma;
>  
>  		anon_vma_lock_read(av);
> -		rcu_read_lock();
> -		for_each_process(tsk) {
> +		for_each_process_rcu(tsk) {
>  			struct anon_vma_chain *vmac;
>  			const unsigned long addr = rmap_item->address & PAGE_MASK;
>  			const unsigned long index = rmap_item->linear_page_index;
> @@ -3298,7 +3297,6 @@ void collect_procs_ksm(const struct folio *folio, const struct page *page,
>  				}
>  			}
>  		}
> -		rcu_read_unlock();
>  		anon_vma_unlock_read(av);
>  	}
>  }
> -- 
> 2.25.1
> 

-- 
Michal Hocko
SUSE Labs