linux-kernel - Re: [PATCH 2/2] f2fs: Enhance the subsequent logic of valid_thresh_ratio to prevent unnecessary background GC

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Message-ID: <b42b161d-cd5d-45dc-8e84-c2b28eb632e5@kernel.org>
Date: Mon, 15 Sep 2025 16:36:55 +0800
From: Chao Yu <chao@...nel.org>
To: Liao Yuanhong <liaoyuanhong@...o.com>, Jaegeuk Kim <jaegeuk@...nel.org>,
 "open list:F2FS FILE SYSTEM" <linux-f2fs-devel@...ts.sourceforge.net>,
 open list <linux-kernel@...r.kernel.org>
Cc: chao@...nel.org
Subject: Re: [PATCH 2/2] f2fs: Enhance the subsequent logic of
 valid_thresh_ratio to prevent unnecessary background GC

On 9/9/25 21:44, Liao Yuanhong wrote:
> When the proportion of dirty segments within a section exceeds the
> valid_thresh_ratio, the gc_cost of that section is set to UINT_MAX,
> indicating that these sections should not be released. However, if all
> section costs within the scanning range of get_victim() are UINT_MAX,
> background GC will still occur. Add a condition to prevent this situation.

For this case, f2fs_get_victim() will return 0, and f2fs_gc() will use unchanged
segno for GC?

Thanks,

> 
> Signed-off-by: Liao Yuanhong <liaoyuanhong@...o.com>
> ---
>  fs/f2fs/gc.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 4a8c08f970e3..ffc3188416f4 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -936,6 +936,11 @@ int f2fs_get_victim(struct f2fs_sb_info *sbi, unsigned int *result,
>  		}
>  	}
>  
> +	if (f2fs_sb_has_blkzoned(sbi) && p.min_cost == UINT_MAX) {
> +		ret = -ENODATA;
> +		goto out;
> +	}
> +
>  	/* get victim for GC_AT/AT_SSR */
>  	if (is_atgc) {
>  		lookup_victim_by_age(sbi, &p);