Re: [PATCH 4/5] mm: rework non-root kmem_cache lifecycle management

[Christopher Lameter <cl@linux.com>]

On Wed, 17 Apr 2019, Roman Gushchin wrote:

>  static __always_inline int memcg_charge_slab(struct page *page,
>  					     gfp_t gfp, int order,
>  					     struct kmem_cache *s)
>  {
> -	if (is_root_cache(s))
> +	int idx = (s->flags & SLAB_RECLAIM_ACCOUNT) ?
> +		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE;
> +	struct mem_cgroup *memcg;
> +	struct lruvec *lruvec;
> +	int ret;
> +
> +	if (is_root_cache(s)) {
> +		mod_node_page_state(page_pgdat(page), idx, 1 << order);

Hmmm... This is functionality that is not memcg specific being moved into
a memcg function??? Maybe rename the function to indicate that it is not
memcg specific and add the proper #ifdefs?

>  static __always_inline void memcg_uncharge_slab(struct page *page, int order,
>  						struct kmem_cache *s)
>  {
> -	memcg_kmem_uncharge(page, order);
> +	int idx = (s->flags & SLAB_RECLAIM_ACCOUNT) ?
> +		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE;
> +	struct mem_cgroup *memcg;
> +	struct lruvec *lruvec;
> +
> +	if (is_root_cache(s)) {
> +		mod_node_page_state(page_pgdat(page), idx, -(1 << order));
> +		return;
> +	}

And again.