From: Chao Yu <chao2.yu@samsung.com>
To: "'Jaegeuk Kim'" <jaegeuk@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
References: <1406328445-63707-1-git-send-email-jaegeuk@kernel.org>
 <1406328445-63707-6-git-send-email-jaegeuk@kernel.org>
In-reply-to: <1406328445-63707-6-git-send-email-jaegeuk@kernel.org>
Subject: RE: [f2fs-dev] [PATCH 06/11] f2fs: skip unnecessary data writes during
	fsync
Date: Tue, 29 Jul 2014 19:39:45 +0800
Message-id: <008201cfab21$e5c57ff0$b1507fd0$@samsung.com>
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Hi,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Saturday, July 26, 2014 6:47 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 06/11] f2fs: skip unnecessary data writes during fsync
> 
> This patch intends to improve the fsync performance by skipping remaining the
> recovery information, only when there is no data that we should recover.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/file.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 7c652b3..121689a 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -133,6 +133,17 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int
> datasync)
>  		return ret;
>  	}
> 
> +	/*
> +	 * if there is no written data, don't waste time to write recovery info.
> +	 */
> +	if (!is_inode_flag_set(fi, FI_APPEND_WRITE) &&
> +		!exist_written_data(sbi, inode->i_ino, APPEND_INO)) {
> +		if (is_inode_flag_set(fi, FI_UPDATE_WRITE) &&
> +			exist_written_data(sbi, inode->i_ino, UPDATE_INO))

Should we shift this to is_inode_flag_set(fi, FI_UPDATE_WRITE) ||
exist_written_data(sbi, inode->i_ino, UPDATE_INO) ?

> +			goto flush_out;
> +		goto out;
> +	}
> +
>  	/* guarantee free sections for fsync */
>  	f2fs_balance_fs(sbi);
> 
> @@ -188,6 +199,11 @@ int f2fs_sync_file(struct file *file, loff_t start, loff_t end, int
> datasync)
>  		ret = wait_on_node_pages_writeback(sbi, inode->i_ino);
>  		if (ret)
>  			goto out;
> +
> +		/* once recovery info is written, don't need to tack this */
> +		remove_dirty_inode(sbi, inode->i_ino, APPEND_INO);
> +flush_out:
> +		remove_dirty_inode(sbi, inode->i_ino, UPDATE_INO);
>  		ret = f2fs_issue_flush(F2FS_SB(inode->i_sb));
>  	}
>  out:
> --
> 1.8.5.2 (Apple Git-48)
> 
> 
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