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

[Ridong Chen <ridong.chen@linux.dev>]

On 7/23/2026 9:59 AM, Johannes Weiner wrote:
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> 
> 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