Re: [PATCH v2 6/6] zswap: memcg accounting

[Michal Koutný]

Hello.

On Tue, May 10, 2022 at 11:28:47AM -0400, Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
> +void obj_cgroup_charge_zswap(struct obj_cgroup *objcg, size_t size)
> +{
> +	struct mem_cgroup *memcg;
> +
> +	VM_WARN_ON_ONCE(!(current->flags & PF_MEMALLOC));
> +
> +	/* PF_MEMALLOC context, charging must succeed */
> +	if (obj_cgroup_charge(objcg, GFP_KERNEL, size))
> +		VM_WARN_ON_ONCE(1);

IIUC, the objcg is derived from the compressed page, i.e. same memcg
(reparenting neglected for now). This memcg's memory.current is then
charged with the compressed object size.

Do I get it right that memory.zswap.current is a subset of memory.current?

(And that zswap is limited both by memory.max and memory.zswap.max?)

Thanks,
Michal