Re: [PATCH 03/10] mm/damon/core: use mult_frac() in damon_feed_loop_next_input()

[Gutierrez Asier]

On 9/17/2026 5:22 PM, SJ Park wrote:
> damon_feed_loop_next_input() does its best effort overflow protection.
> score_goal_diff is always smaller than goal (10,000).  Hence the
> calculation can be replaced to use mult_frac() without concerning the
> overflow.  Use mult_frac().
> 
> Signed-off-by: SJ Park <sj@xxxxxxxxxx>
> ---
>  mm/damon/core.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index de46072dc1a2f..bc41ac7ecca43 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -2927,11 +2927,7 @@ static unsigned long damon_feed_loop_next_input(unsigned long last_input,
>  		return min_input;
>  
>  	score_goal_diff = abs_diff(score, goal);
> -
> -	if (last_input < ULONG_MAX / score_goal_diff)
> -		compensation = last_input * score_goal_diff / goal;
> -	else
> -		compensation = last_input / goal * score_goal_diff;
> +	compensation = mult_frac(last_input, score_goal_diff, goal);
>  
>  	if (over_achieving)
>  		return max(last_input - compensation, min_input);
LGTM

Reviewed-by: Asier Gutierrez <gutierrez.asier@xxxxxxxxxxxxxxxxxxx>


-- 
Asier Gutierrez
Huawei