Re: [PATCH] memcg: Don't wait writeback completion when release memcg.

[Tejun Heo <tj@xxxxxxxxxx>]

On Wed, Aug 20, 2025 at 07:19:40PM +0800, Julian Sun wrote:
> @@ -3912,8 +3921,12 @@ static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
>  	int __maybe_unused i;
>  
>  #ifdef CONFIG_CGROUP_WRITEBACK
> -	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
> -		wb_wait_for_completion(&memcg->cgwb_frn[i].done);
> +	for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
> +		struct wb_completion *done = memcg->cgwb_frn[i].done;
> +
> +		if (atomic_dec_and_test(&done->cnt))
> +			kfree(done);
> +	}
>  #endif

Can't you just remove done? I don't think it's doing anything after your
changes anyway.

Thanks.

-- 
tejun