Re: [RFC 1/3] headers: add more types to linux/types.h

[Matthew Wilcox]

On Tue, Dec 07, 2021 at 04:09:25PM +0100, Arnd Bergmann wrote:
> +struct list_lru {
> +	struct list_lru_node	*node;
> +#ifdef CONFIG_MEMCG_KMEM
> +	struct list_head	list;
> +	int			shrinker_id;
> +	bool			memcg_aware;
> +#endif
> +};

This is the only one that gives me qualms.  While there are other
CONFIG options mentioned in types.h they're properties of the platform,
eg CONFIG_HAVE_UID16, CONFIG_64BIT, CONFIG_ARCH_DMA_ADDR_T_64BIT, etc.
I dislike it that changing this CONFIG option is going to result in
rebuilding the _entire_ kernel.  CONFIG_MEMCG_KMEM just isn't that
central to how everything works.