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Date:   Mon, 24 Jul 2023 14:25:49 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Qi Zheng <zhengqi.arch@bytedance.com>
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Subject: Re: [PATCH v2 03/47] mm: shrinker: add infrastructure for
 dynamically allocating shrinker
Message-ID: <20230724122549.GA3731903@hirez.programming.kicks-ass.net>
References: <20230724094354.90817-1-zhengqi.arch@bytedance.com>
 <20230724094354.90817-4-zhengqi.arch@bytedance.com>
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On Mon, Jul 24, 2023 at 05:43:10PM +0800, Qi Zheng wrote:

> +void shrinker_unregister(struct shrinker *shrinker)
> +{
> +	struct dentry *debugfs_entry;
> +	int debugfs_id;
> +
> +	if (!shrinker || !(shrinker->flags & SHRINKER_REGISTERED))
> +		return;
> +
> +	down_write(&shrinker_rwsem);
> +	list_del(&shrinker->list);
> +	shrinker->flags &= ~SHRINKER_REGISTERED;
> +	if (shrinker->flags & SHRINKER_MEMCG_AWARE)
> +		unregister_memcg_shrinker(shrinker);
> +	debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id);
> +	up_write(&shrinker_rwsem);
> +
> +	shrinker_debugfs_remove(debugfs_entry, debugfs_id);

Should there not be an rcu_barrier() right about here?

> +
> +	kfree(shrinker->nr_deferred);
> +	shrinker->nr_deferred = NULL;
> +
> +	kfree(shrinker);
> +}
> +EXPORT_SYMBOL(shrinker_unregister);