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Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: do not select same victim right
 again
To:     Jaegeuk Kim <jaegeuk@kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>
References: <20190909012532.20454-1-jaegeuk@kernel.org>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <69933b7f-48cc-47f9-ba6f-b5ca8f733cba@huawei.com>
Date:   Mon, 9 Sep 2019 10:56:57 +0800
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On 2019/9/9 9:25, Jaegeuk Kim wrote:
> GC must avoid select the same victim again.

Blocks in previous victim will occupy addition free segment, I doubt after this
change, FGGC may encounter out-of-free space issue more frequently.

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/gc.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index e88f98ddf396..15ca8bbb0b22 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -274,6 +274,9 @@ static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned int segno)
>  static inline unsigned int get_gc_cost(struct f2fs_sb_info *sbi,
>  			unsigned int segno, struct victim_sel_policy *p)
>  {
> +	if (sbi->cur_victim_sec == GET_SEC_FROM_SEG(sbi, segno))
> +		return UINT_MAX;
> +
>  	if (p->alloc_mode == SSR)
>  		return get_seg_entry(sbi, segno)->ckpt_valid_blocks;
>  
> @@ -1326,9 +1329,6 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
>  		round++;
>  	}
>  
> -	if (gc_type == FG_GC)
> -		sbi->cur_victim_sec = NULL_SEGNO;
> -
>  	if (sync)
>  		goto stop;
>  
>