Re: [PATCH v2 2/2] mm/vmscan: check all allowed targets in can_demote()

[Bing Jiao <bingjiao@google.com>]

On Mon, Dec 22, 2025 at 10:51:49AM +0800, Chen Ridong wrote:
>
>
> On 2025/12/22 7:36, Bing Jiao wrote:
> > -void cpuset_node_filter_allowed(struct cgroup *cgroup, nodemask_t *mask)
> > -{
> > -	struct cgroup_subsys_state *css;
> > -	struct cpuset *cs;
> > -
> > -	if (!cpuset_v2())
> > -		return;
> > -
> > -	css = cgroup_get_e_css(cgroup, &cpuset_cgrp_subsys);
> > -	if (!css)
> > -		return;
> > -
> > -	/* Follows the same assumption in cpuset_node_allowed() */
> > -	cs = container_of(css, struct cpuset, css);
> >  	nodes_and(*mask, *mask, cs->effective_mems);
> >  	css_put(css);
> >  }
>
> Oh, I see you merged these two functions here.
>
> However, I think cpuset_get_mem_allowed would be more versatile in general use.
>
> You can then check whether the returned nodemask intersects with your target mask. In the future,
> there may be scenarios where users simply want to retrieve the effective masks directly.
>

Hi Ridong, thank you for the suggestions.

I agree that returning a nodemask would provide greater versatility.

I think cpuset_get_mem_allowed_relax() would be a better name,
since we do not need the locking and online mem guarantees
compared to an similar function cpuset_mems_allowed().

Best,
Bing