Re: [PATCH v2 1/2] memcg: move mem_cgroup_swappiness and vm_swappiness to mm/swap.h

[Ridong Chen]

On 7/23/2026 9:59 AM, Johannes Weiner wrote:
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
>
> One small suggestion:
>
> On Thu, Jul 16, 2026 at 11:17:28AM +0800, Ridong wrote:
> > @@ -76,6 +77,25 @@ enum swap_cluster_flags {
> >   	CLUSTER_FLAG_MAX,
> >   };
> >   
> > +extern int vm_swappiness;
> > +
> > +static inline int mem_cgroup_swappiness(struct mem_cgroup *memcg)
> > +{
> > +#ifdef CONFIG_MEMCG_V1
> > +	/* Cgroup2 doesn't have per-cgroup swappiness */
> > +	if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
> > +		return READ_ONCE(vm_swappiness);
> > +
> > +	/* root ? */
> > +	if (mem_cgroup_disabled() || mem_cgroup_is_root(memcg))
> > +		return READ_ONCE(vm_swappiness);
> > +
> > +	return READ_ONCE(memcg->swappiness);
> > +#else
> > +	return READ_ONCE(vm_swappiness);
> > +#endif
>
> How about:
>
> #ifdef CONFIG_MEMCG_V1
> 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
> 	    !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg))
> 		return memcg->swappiness;
> #endif
> 	return READ_ONCE(vm_swappiness);

This is simpler.

Hi, Andrew, I notice you just applied this series to mm-new branch. Would you 
mind I update it?

--
Best regards
Ridong