Re: [PATCH] f2fs: remove request_list check in is_idle()

[Chao Yu <chao@kernel.org>]

Hi Jens,

On 2018-10-16 22:34, Jens Axboe wrote:
> This doesn't work on stacked devices, and it doesn't work on
> blk-mq devices. The request_list is only used on legacy, which
> we don't have much of anymore, and soon won't have any of.
> 
> Kill the check.

In order to avoid conflicting with user IO, GC and Discard thread try to be
aware of IO status of device by is_idle(), if previous implementation doesn't
work, do we have any other existing method to get such status? Or do you have
any suggestion on this?

Thanks,

> 
> Cc: Jaegeuk Kim <jaegeuk@kernel.org>
> Cc: linux-f2fs-devel@lists.sourceforge.net
> Signed-off-by: Jens Axboe <axboe@kernel.dk>
> ---
>  fs/f2fs/f2fs.h | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index abf925664d9c..58778992eca4 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -1356,13 +1356,6 @@ static inline bool f2fs_time_over(struct f2fs_sb_info *sbi, int type)
>  
>  static inline bool is_idle(struct f2fs_sb_info *sbi)
>  {
> -	struct block_device *bdev = sbi->sb->s_bdev;
> -	struct request_queue *q = bdev_get_queue(bdev);
> -	struct request_list *rl = &q->root_rl;
> -
> -	if (rl->count[BLK_RW_SYNC] || rl->count[BLK_RW_ASYNC])
> -		return false;
> -
>  	return f2fs_time_over(sbi, REQ_TIME);
>  }
>  
>