diff mbox series

[v6,1/5] writeback, cgroup: switch to rcu_work API in inode_switch_wbs()

Message ID 20210603005517.1403689-2-guro@fb.com (mailing list archive)
State New
Headers show
Series cgroup, blkcg: prevent dirty inodes to pin dying memory cgroups | expand

Commit Message

Roman Gushchin June 3, 2021, 12:55 a.m. UTC
Inode's wb switching requires two steps divided by an RCU grace
period. It's currently implemented as an RCU callback
inode_switch_wbs_rcu_fn(), which schedules inode_switch_wbs_work_fn()
as a work.

Switching to the rcu_work API allows to do the same in a cleaner and
slightly shorter form.

Signed-off-by: Roman Gushchin <guro@fb.com>
---
 fs/fs-writeback.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

Comments

Jan Kara June 3, 2021, 8:46 a.m. UTC | #1
On Wed 02-06-21 17:55:13, Roman Gushchin wrote:
> Inode's wb switching requires two steps divided by an RCU grace
> period. It's currently implemented as an RCU callback
> inode_switch_wbs_rcu_fn(), which schedules inode_switch_wbs_work_fn()
> as a work.
> 
> Switching to the rcu_work API allows to do the same in a cleaner and
> slightly shorter form.
> 
> Signed-off-by: Roman Gushchin <guro@fb.com>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/fs-writeback.c | 18 ++++--------------
>  1 file changed, 4 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index e91980f49388..1f51857e41d1 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -335,8 +335,7 @@ struct inode_switch_wbs_context {
>  	struct inode		*inode;
>  	struct bdi_writeback	*new_wb;
>  
> -	struct rcu_head		rcu_head;
> -	struct work_struct	work;
> +	struct rcu_work		work;
>  };
>  
>  static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi)
> @@ -352,7 +351,7 @@ static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi)
>  static void inode_switch_wbs_work_fn(struct work_struct *work)
>  {
>  	struct inode_switch_wbs_context *isw =
> -		container_of(work, struct inode_switch_wbs_context, work);
> +		container_of(to_rcu_work(work), struct inode_switch_wbs_context, work);
>  	struct inode *inode = isw->inode;
>  	struct backing_dev_info *bdi = inode_to_bdi(inode);
>  	struct address_space *mapping = inode->i_mapping;
> @@ -469,16 +468,6 @@ static void inode_switch_wbs_work_fn(struct work_struct *work)
>  	atomic_dec(&isw_nr_in_flight);
>  }
>  
> -static void inode_switch_wbs_rcu_fn(struct rcu_head *rcu_head)
> -{
> -	struct inode_switch_wbs_context *isw = container_of(rcu_head,
> -				struct inode_switch_wbs_context, rcu_head);
> -
> -	/* needs to grab bh-unsafe locks, bounce to work item */
> -	INIT_WORK(&isw->work, inode_switch_wbs_work_fn);
> -	queue_work(isw_wq, &isw->work);
> -}
> -
>  /**
>   * inode_switch_wbs - change the wb association of an inode
>   * @inode: target inode
> @@ -534,7 +523,8 @@ static void inode_switch_wbs(struct inode *inode, int new_wb_id)
>  	 * lock so that stat transfer can synchronize against them.
>  	 * Let's continue after I_WB_SWITCH is guaranteed to be visible.
>  	 */
> -	call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);
> +	INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn);
> +	queue_rcu_work(isw_wq, &isw->work);
>  
>  	atomic_inc(&isw_nr_in_flight);
>  	return;
> -- 
> 2.31.1
>
diff mbox series

Patch

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index e91980f49388..1f51857e41d1 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -335,8 +335,7 @@  struct inode_switch_wbs_context {
 	struct inode		*inode;
 	struct bdi_writeback	*new_wb;
 
-	struct rcu_head		rcu_head;
-	struct work_struct	work;
+	struct rcu_work		work;
 };
 
 static void bdi_down_write_wb_switch_rwsem(struct backing_dev_info *bdi)
@@ -352,7 +351,7 @@  static void bdi_up_write_wb_switch_rwsem(struct backing_dev_info *bdi)
 static void inode_switch_wbs_work_fn(struct work_struct *work)
 {
 	struct inode_switch_wbs_context *isw =
-		container_of(work, struct inode_switch_wbs_context, work);
+		container_of(to_rcu_work(work), struct inode_switch_wbs_context, work);
 	struct inode *inode = isw->inode;
 	struct backing_dev_info *bdi = inode_to_bdi(inode);
 	struct address_space *mapping = inode->i_mapping;
@@ -469,16 +468,6 @@  static void inode_switch_wbs_work_fn(struct work_struct *work)
 	atomic_dec(&isw_nr_in_flight);
 }
 
-static void inode_switch_wbs_rcu_fn(struct rcu_head *rcu_head)
-{
-	struct inode_switch_wbs_context *isw = container_of(rcu_head,
-				struct inode_switch_wbs_context, rcu_head);
-
-	/* needs to grab bh-unsafe locks, bounce to work item */
-	INIT_WORK(&isw->work, inode_switch_wbs_work_fn);
-	queue_work(isw_wq, &isw->work);
-}
-
 /**
  * inode_switch_wbs - change the wb association of an inode
  * @inode: target inode
@@ -534,7 +523,8 @@  static void inode_switch_wbs(struct inode *inode, int new_wb_id)
 	 * lock so that stat transfer can synchronize against them.
 	 * Let's continue after I_WB_SWITCH is guaranteed to be visible.
 	 */
-	call_rcu(&isw->rcu_head, inode_switch_wbs_rcu_fn);
+	INIT_RCU_WORK(&isw->work, inode_switch_wbs_work_fn);
+	queue_rcu_work(isw_wq, &isw->work);
 
 	atomic_inc(&isw_nr_in_flight);
 	return;