Re: [RFC PATCH v4 1/7] mm/demotion: Add support for explicit memory tiers

[Ying Huang]

On Fri, 2022-05-27 at 17:55 +0530, Aneesh Kumar K.V wrote:

[snip]

> 
> +static int __init memory_tier_init(void)
> +{
> +	int ret;
> +
> +	ret = subsys_system_register(&memory_tier_subsys, memory_tier_attr_groups);
> +	if (ret)
> +		panic("%s() failed to register subsystem: %d\n", __func__, ret);

I don't think we should go panic for failing to register subsys and
device for memory tiers.  Just pr_err() should be enough.

Best Regards,
Huang, Ying

> +
> +	/*
> +	 * Register only default memory tier to hide all empty
> +	 * memory tier from sysfs.
> +	 */
> +	ret = register_memory_tier(DEFAULT_MEMORY_TIER);
> +	if (ret)
> +		panic("%s() failed to register memory tier: %d\n", __func__, ret);
> +
> +	/*
> +	 * CPU only nodes are not part of memoty tiers.
> +	 */
> +	memory_tiers[DEFAULT_MEMORY_TIER]->nodelist = node_states[N_MEMORY];
> +
> +	return 0;
> +}
> +subsys_initcall(memory_tier_init);
> +
> +#endif	/* CONFIG_TIERED_MEMORY */