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Date: Fri, 19 Jan 2024 16:26:59 +0100
From: Jan Kara <jack@suse.cz>
To: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz,
	akpm@linux-foundation.org, tj@kernel.org, xiujianfeng@huawei.com,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] writeback: move wb_wakeup_delayed defination to
 fs-writeback.c
Message-ID: <20240119152659.fvfk2axsd2pwhebk@quack3>
References: <20240118203339.764093-1-shikemeng@huaweicloud.com>
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In-Reply-To: <20240118203339.764093-1-shikemeng@huaweicloud.com>

On Fri 19-01-24 04:33:39, Kemeng Shi wrote:
> The wb_wakeup_delayed is only used in fs-writeback.c. Move it to
> fs-writeback.c after defination of wb_wakeup and make it static.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Yeah, not sure why it was left there. Feel free to add:

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

								Honza

> ---
>  fs/fs-writeback.c           | 25 +++++++++++++++++++++++++
>  include/linux/backing-dev.h |  1 -
>  mm/backing-dev.c            | 25 -------------------------
>  3 files changed, 25 insertions(+), 26 deletions(-)
> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index 1767493dffda..5ab1aaf805f7 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -141,6 +141,31 @@ static void wb_wakeup(struct bdi_writeback *wb)
>  	spin_unlock_irq(&wb->work_lock);
>  }
>  
> +/*
> + * This function is used when the first inode for this wb is marked dirty. It
> + * wakes-up the corresponding bdi thread which should then take care of the
> + * periodic background write-out of dirty inodes. Since the write-out would
> + * starts only 'dirty_writeback_interval' centisecs from now anyway, we just
> + * set up a timer which wakes the bdi thread up later.
> + *
> + * Note, we wouldn't bother setting up the timer, but this function is on the
> + * fast-path (used by '__mark_inode_dirty()'), so we save few context switches
> + * by delaying the wake-up.
> + *
> + * We have to be careful not to postpone flush work if it is scheduled for
> + * earlier. Thus we use queue_delayed_work().
> + */
> +static void wb_wakeup_delayed(struct bdi_writeback *wb)
> +{
> +	unsigned long timeout;
> +
> +	timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
> +	spin_lock_irq(&wb->work_lock);
> +	if (test_bit(WB_registered, &wb->state))
> +		queue_delayed_work(bdi_wq, &wb->dwork, timeout);
> +	spin_unlock_irq(&wb->work_lock);
> +}
> +
>  static void finish_writeback_work(struct bdi_writeback *wb,
>  				  struct wb_writeback_work *work)
>  {
> diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
> index 1a97277f99b1..8e7af9a03b41 100644
> --- a/include/linux/backing-dev.h
> +++ b/include/linux/backing-dev.h
> @@ -38,7 +38,6 @@ struct backing_dev_info *bdi_alloc(int node_id);
>  
>  void wb_start_background_writeback(struct bdi_writeback *wb);
>  void wb_workfn(struct work_struct *work);
> -void wb_wakeup_delayed(struct bdi_writeback *wb);
>  
>  void wb_wait_for_completion(struct wb_completion *done);
>  
> diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> index 1e3447bccdb1..039dc74b505a 100644
> --- a/mm/backing-dev.c
> +++ b/mm/backing-dev.c
> @@ -372,31 +372,6 @@ static int __init default_bdi_init(void)
>  }
>  subsys_initcall(default_bdi_init);
>  
> -/*
> - * This function is used when the first inode for this wb is marked dirty. It
> - * wakes-up the corresponding bdi thread which should then take care of the
> - * periodic background write-out of dirty inodes. Since the write-out would
> - * starts only 'dirty_writeback_interval' centisecs from now anyway, we just
> - * set up a timer which wakes the bdi thread up later.
> - *
> - * Note, we wouldn't bother setting up the timer, but this function is on the
> - * fast-path (used by '__mark_inode_dirty()'), so we save few context switches
> - * by delaying the wake-up.
> - *
> - * We have to be careful not to postpone flush work if it is scheduled for
> - * earlier. Thus we use queue_delayed_work().
> - */
> -void wb_wakeup_delayed(struct bdi_writeback *wb)
> -{
> -	unsigned long timeout;
> -
> -	timeout = msecs_to_jiffies(dirty_writeback_interval * 10);
> -	spin_lock_irq(&wb->work_lock);
> -	if (test_bit(WB_registered, &wb->state))
> -		queue_delayed_work(bdi_wq, &wb->dwork, timeout);
> -	spin_unlock_irq(&wb->work_lock);
> -}
> -
>  static void wb_update_bandwidth_workfn(struct work_struct *work)
>  {
>  	struct bdi_writeback *wb = container_of(to_delayed_work(work),
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR