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Date: Fri, 23 Feb 2024 14:58:09 +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,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 5/7] fs/writeback: only calculate dirtied_before when
 b_io is empty
Message-ID: <20240223135809.5bvyl7ex3zm6bnta@quack3>
References: <20240208172024.23625-1-shikemeng@huaweicloud.com>
 <20240208172024.23625-6-shikemeng@huaweicloud.com>
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In-Reply-To: <20240208172024.23625-6-shikemeng@huaweicloud.com>

On Fri 09-02-24 01:20:22, Kemeng Shi wrote:
> The dirtied_before is only used when b_io is not empty, so only calculate
> when b_io is not empty.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>  fs/fs-writeback.c | 25 +++++++++++++------------
>  1 file changed, 13 insertions(+), 12 deletions(-)

OK, but please wrap the comment at 80 columns as well.

								Honza

> 
> diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
> index b61bf2075931..e8868e814e0a 100644
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -2118,20 +2118,21 @@ static long wb_writeback(struct bdi_writeback *wb,
>  
>  		spin_lock(&wb->list_lock);
>  
> -		/*
> -		 * Kupdate and background works are special and we want to
> -		 * include all inodes that need writing. Livelock avoidance is
> -		 * handled by these works yielding to any other work so we are
> -		 * safe.
> -		 */
> -		if (work->for_kupdate) {
> -			dirtied_before = jiffies -
> -				msecs_to_jiffies(dirty_expire_interval * 10);
> -		} else if (work->for_background)
> -			dirtied_before = jiffies;
> -
>  		trace_writeback_start(wb, work);
>  		if (list_empty(&wb->b_io)) {
> +			/*
> +			 * Kupdate and background works are special and we want to
> +			 * include all inodes that need writing. Livelock avoidance is
> +			 * handled by these works yielding to any other work so we are
> +			 * safe.
> +			 */
> +			if (work->for_kupdate) {
> +				dirtied_before = jiffies -
> +					msecs_to_jiffies(dirty_expire_interval *
> +							 10);
> +			} else if (work->for_background)
> +				dirtied_before = jiffies;
> +
>  			queue_io(wb, work, dirtied_before);
>  			queued = true;
>  		}
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR