Re: [f2fs-dev] [PATCH] f2fs: add iostat tracking for direct IO

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

On 4/23/26 11:42, liujinbao1 wrote:
> From: liujinbao1 <liujinbao1@xiaomi.com>
> 
> F2FS did not collect iostat statistics for direct IO reads and writes,
> hook submit_io to bind an iostat context and record the submission
> timestamp, replace bi_end_io to collect IO latency on completion and
> then call back to the original iomap_dio_bio_end_io(), to add iostat
> tracking support for F2FS DIO.

Not sure, do we need to distinguish the latency of DIO from buffered IO?

> 
> Signed-off-by: shengyong1 <shengyong1@xiaomi.com>
> Signed-off-by: liujinbao1 <liujinbao1@xiaomi.com>
> ---
>   fs/f2fs/file.c   | 27 +++++++++++++++++++++++++++
>   fs/f2fs/iostat.c |  2 +-
>   2 files changed, 28 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 2c4880f24b54..fcf725931fd8 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -4774,6 +4774,16 @@ static bool f2fs_should_use_dio(struct inode *inode, struct kiocb *iocb,
>   	return true;
>   }
>   
> +static void f2fs_dio_end_bio(struct bio *bio)
> +{
> +	struct bio_iostat_ctx *iostat_ctx = bio->bi_private;
> +	void *orig_bi_private = iostat_ctx->post_read_ctx;
> +
> +	iostat_update_and_unbind_ctx(bio);
> +	bio->bi_private = orig_bi_private;
> +	iomap_dio_bio_end_io(bio);
> +}
> +
>   static int f2fs_dio_read_end_io(struct kiocb *iocb, ssize_t size, int error,
>   				unsigned int flags)
>   {
> @@ -4786,8 +4796,21 @@ static int f2fs_dio_read_end_io(struct kiocb *iocb, ssize_t size, int error,
>   	return 0;
>   }
>   
> +static void f2fs_dio_read_submit_io(const struct iomap_iter *iter,
> +					struct bio *bio, loff_t file_offset)
> +{
> +	struct f2fs_sb_info *sbi = F2FS_I_SB(iter->inode);
> +	void *bi_private = bio->bi_private;
> +
> +	iostat_alloc_and_bind_ctx(sbi, bio, bi_private);
> +	iostat_update_submit_ctx(bio, DATA);
> +	bio->bi_end_io = f2fs_dio_end_bio;
> +	blk_crypto_submit_bio(bio);
> +}
> +
>   static const struct iomap_dio_ops f2fs_iomap_dio_read_ops = {
>   	.end_io = f2fs_dio_read_end_io,
> +	.submit_io = f2fs_dio_read_submit_io,
>   };
>   
>   static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
> @@ -5064,8 +5087,12 @@ static void f2fs_dio_write_submit_io(const struct iomap_iter *iter,
>   	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>   	enum log_type type = f2fs_rw_hint_to_seg_type(sbi, inode->i_write_hint);
>   	enum temp_type temp = f2fs_get_segment_temp(sbi, type);
> +	void *bi_private = bio->bi_private;
>   
>   	bio->bi_write_hint = f2fs_io_type_to_rw_hint(sbi, DATA, temp);
> +	iostat_alloc_and_bind_ctx(sbi, bio, bi_private);
> +	iostat_update_submit_ctx(bio, DATA);
> +	bio->bi_end_io = f2fs_dio_end_bio;
>   	blk_crypto_submit_bio(bio);

There are duplicated codes in f2fs_dio_write_submit_io() and f2fs_dio_read_submit_io(),
can we introduce a common function to wrap those codes?

Thanks,

>   }
>   
> diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
> index f8703038e1d8..57d2c3e68a1b 100644
> --- a/fs/f2fs/iostat.c
> +++ b/fs/f2fs/iostat.c
> @@ -218,7 +218,7 @@ static inline void __update_iostat_latency(struct bio_iostat_ctx *iostat_ctx,
>   	struct iostat_lat_info *io_lat = sbi->iostat_io_lat;
>   	unsigned long flags;
>   
> -	if (!sbi->iostat_enable)
> +	if (!sbi->iostat_enable || iostat_ctx->submit_ts == 0)
>   		return;
>   
>   	ts_diff = jiffies - iostat_ctx->submit_ts;



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