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Date:   Sun, 11 Dec 2022 10:23:23 +0800
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Subject: Re: [PATCH] f2fs: fix iostat parameter for discard
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To:     Yangtao Li <frank.li@vivo.com>, jaegeuk@kernel.org
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
References: <20221205145603.70779-1-frank.li@vivo.com>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <20221205145603.70779-1-frank.li@vivo.com>
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On 2022/12/5 22:56, Yangtao Li wrote:
> Just like other data we count uses the number of bytes as the basic unit,
> but discard uses the number of cmds as the statistical unit. In fact the
> discard command contains the number of blocks, so let's change to the
> number of bytes as the base unit.
> 
> Fixes: b0af6d491a6b ("f2fs: add app/fs io stat")
> 
> Signed-off-by: Yangtao Li <frank.li@vivo.com>
> ---
>   fs/f2fs/segment.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 9486ca49ecb1..bc262e17b279 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1181,7 +1181,7 @@ static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>   
>   		atomic_inc(&dcc->issued_discard);
>   
> -		f2fs_update_iostat(sbi, NULL, FS_DISCARD, 1);
> +		f2fs_update_iostat(sbi, NULL, FS_DISCARD, len * F2FS_BLKSIZE);

In order to avoid breaking its usage of application, how about keeping
FS_DISCARD as it is, and add FS_DISCARD_IO to account discard bytes?

Thanks,

>   
>   		lstart += len;
>   		start += len;