Re: [PATCH v2 03/47] mm: shrinker: add infrastructure for dynamically allocating shrinker

[Peter Zijlstra]

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);