diff mbox series

mm/memcontrol: remove the unnecessary rcu_read_[un]lock

Message ID 20201216055213.GA63520@rlk (mailing list archive)
State New, archived
Headers show
Series mm/memcontrol: remove the unnecessary rcu_read_[un]lock | expand

Commit Message

Hui Su Dec. 16, 2020, 5:52 a.m. UTC
the rcu_read_lock and rcu_read_unlock is unnecessary in:
	lock_page_lruvec()
	lock_page_lruvec_irq()
	lock_page_lruvec_irqsave()

Signed-off-by: Hui Su <sh_def@163.com>
---
 mm/memcontrol.c | 6 ------
 1 file changed, 6 deletions(-)

Comments

Michal Hocko Dec. 16, 2020, 7:35 a.m. UTC | #1
On Wed 16-12-20 13:52:13, Hui Su wrote:
> the rcu_read_lock and rcu_read_unlock is unnecessary in:
> 	lock_page_lruvec()
> 	lock_page_lruvec_irq()
> 	lock_page_lruvec_irqsave()

Please add an explanation why it is unnecessary.

> Signed-off-by: Hui Su <sh_def@163.com>
> ---
>  mm/memcontrol.c | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index e3c7ca7dc174..a19f820e8a3f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1396,10 +1396,8 @@ struct lruvec *lock_page_lruvec(struct page *page)
>  	struct lruvec *lruvec;
>  	struct pglist_data *pgdat = page_pgdat(page);
>  
> -	rcu_read_lock();
>  	lruvec = mem_cgroup_page_lruvec(page, pgdat);
>  	spin_lock(&lruvec->lru_lock);
> -	rcu_read_unlock();
>  
>  	lruvec_memcg_debug(lruvec, page);
>  
> @@ -1411,10 +1409,8 @@ struct lruvec *lock_page_lruvec_irq(struct page *page)
>  	struct lruvec *lruvec;
>  	struct pglist_data *pgdat = page_pgdat(page);
>  
> -	rcu_read_lock();
>  	lruvec = mem_cgroup_page_lruvec(page, pgdat);
>  	spin_lock_irq(&lruvec->lru_lock);
> -	rcu_read_unlock();
>  
>  	lruvec_memcg_debug(lruvec, page);
>  
> @@ -1426,10 +1422,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
>  	struct lruvec *lruvec;
>  	struct pglist_data *pgdat = page_pgdat(page);
>  
> -	rcu_read_lock();
>  	lruvec = mem_cgroup_page_lruvec(page, pgdat);
>  	spin_lock_irqsave(&lruvec->lru_lock, *flags);
> -	rcu_read_unlock();
>  
>  	lruvec_memcg_debug(lruvec, page);
>  
> -- 
> 2.29.2
diff mbox series

Patch

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e3c7ca7dc174..a19f820e8a3f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1396,10 +1396,8 @@  struct lruvec *lock_page_lruvec(struct page *page)
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock(&lruvec->lru_lock);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);
 
@@ -1411,10 +1409,8 @@  struct lruvec *lock_page_lruvec_irq(struct page *page)
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock_irq(&lruvec->lru_lock);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);
 
@@ -1426,10 +1422,8 @@  struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags)
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = page_pgdat(page);
 
-	rcu_read_lock();
 	lruvec = mem_cgroup_page_lruvec(page, pgdat);
 	spin_lock_irqsave(&lruvec->lru_lock, *flags);
-	rcu_read_unlock();
 
 	lruvec_memcg_debug(lruvec, page);