Re: [f2fs-dev] [PATCH 1/2] f2fs: revert segment allocation for direct IO

[Chao Yu]

On 2016/11/12 5:03, Jaegeuk Kim wrote:
> Now we don't need to be too much careful about storage alignment for dio, since
> its speed becomes quite fast and we'd better avoid any misalignment first.
> 
> Revert: 38aa0889b250 (f2fs: align direct_io'ed data to section)
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>

Reviewed-by: Chao Yu <yuchao0@xxxxxxxxxx>

Thanks,

> ---
>  fs/f2fs/data.c    |  6 +-----
>  fs/f2fs/f2fs.h    |  1 -
>  fs/f2fs/segment.c | 36 +++++++++---------------------------
>  3 files changed, 10 insertions(+), 33 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 47ded0c..ca53da5 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -588,7 +588,6 @@ static int __allocate_data_block(struct dnode_of_data *dn)
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
>  	struct f2fs_summary sum;
>  	struct node_info ni;
> -	int seg = CURSEG_WARM_DATA;
>  	pgoff_t fofs;
>  	blkcnt_t count = 1;
>  
> @@ -606,11 +605,8 @@ static int __allocate_data_block(struct dnode_of_data *dn)
>  	get_node_info(sbi, dn->nid, &ni);
>  	set_summary(&sum, dn->nid, dn->ofs_in_node, ni.version);
>  
> -	if (dn->ofs_in_node == 0 && dn->inode_page == dn->node_page)
> -		seg = CURSEG_DIRECT_IO;
> -
>  	allocate_data_block(sbi, NULL, dn->data_blkaddr, &dn->data_blkaddr,
> -								&sum, seg);
> +						&sum, CURSEG_WARM_DATA);
>  	set_data_blkaddr(dn);
>  
>  	/* update i_size */
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index a6e2ede..0496e82 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -591,7 +591,6 @@ enum {
>  	CURSEG_WARM_NODE,	/* direct node blocks of normal files */
>  	CURSEG_COLD_NODE,	/* indirect node blocks */
>  	NO_CHECK_TYPE,
> -	CURSEG_DIRECT_IO,	/* to use for the direct IO path */
>  };
>  
>  struct flush_cmd {
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 7fb7dd3..4cc589a 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1346,25 +1346,21 @@ static void allocate_segment_by_default(struct f2fs_sb_info *sbi,
>  	stat_inc_seg_type(sbi, curseg);
>  }
>  
> -static void __allocate_new_segments(struct f2fs_sb_info *sbi, int type)
> -{
> -	struct curseg_info *curseg = CURSEG_I(sbi, type);
> -	unsigned int old_segno;
> -
> -	old_segno = curseg->segno;
> -	SIT_I(sbi)->s_ops->allocate_segment(sbi, type, true);
> -	locate_dirty_segment(sbi, old_segno);
> -}
> -
>  void allocate_new_segments(struct f2fs_sb_info *sbi)
>  {
> +	struct curseg_info *curseg;
> +	unsigned int old_segno;
>  	int i;
>  
>  	if (test_opt(sbi, LFS))
>  		return;
>  
> -	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++)
> -		__allocate_new_segments(sbi, i);
> +	for (i = CURSEG_HOT_DATA; i <= CURSEG_COLD_DATA; i++) {
> +		curseg = CURSEG_I(sbi, i);
> +		old_segno = curseg->segno;
> +		SIT_I(sbi)->s_ops->allocate_segment(sbi, i, true);
> +		locate_dirty_segment(sbi, old_segno);
> +	}
>  }
>  
>  static const struct segment_allocation default_salloc_ops = {
> @@ -1498,25 +1494,11 @@ void allocate_data_block(struct f2fs_sb_info *sbi, struct page *page,
>  		struct f2fs_summary *sum, int type)
>  {
>  	struct sit_info *sit_i = SIT_I(sbi);
> -	struct curseg_info *curseg;
> -	bool direct_io = (type == CURSEG_DIRECT_IO);
> -
> -	if (direct_io) {
> -		if (sbi->active_logs <= 4)
> -			type = CURSEG_HOT_DATA;
> -		else
> -			type = CURSEG_WARM_DATA;
> -	}
> -	curseg = CURSEG_I(sbi, type);
> +	struct curseg_info *curseg = CURSEG_I(sbi, type);
>  
>  	mutex_lock(&curseg->curseg_mutex);
>  	mutex_lock(&sit_i->sentry_lock);
>  
> -	/* direct_io'ed data is aligned to the segment for better performance */
> -	if (direct_io && curseg->next_blkoff &&
> -				!has_not_enough_free_secs(sbi, 0, 0))
> -		__allocate_new_segments(sbi, type);
> -
>  	*new_blkaddr = NEXT_FREE_BLKADDR(sbi, curseg);
>  
>  	/*
>