Re: [PATCH v9 4/8] mm/demotion: Add hotplug callbacks to handle new numa node onlined

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

Alistair Popple <apopple@nvidia.com> writes:

> "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes:
>
>> If the new NUMA node onlined doesn't have a memory tier assigned,
>> the kernel adds the NUMA node to default memory tier.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>  mm/memory-tiers.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 68 insertions(+)
>>
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> index 79347d4ab05e..5706ad647136 100644
>> --- a/mm/memory-tiers.c
>> +++ b/mm/memory-tiers.c
>> @@ -5,6 +5,7 @@
>>  #include <linux/slab.h>
>>  #include <linux/lockdep.h>
>>  #include <linux/moduleparam.h>
>> +#include <linux/memory.h>
>>  #include <linux/memory-tiers.h>
>>
>>  struct memory_tier {
>> @@ -130,8 +131,73 @@ int node_create_and_set_memory_tier(int node, int tier)
>>  }
>>  EXPORT_SYMBOL_GPL(node_create_and_set_memory_tier);
>>
>> +static int __node_set_memory_tier(int node, int tier)
>> +{
>> +	int ret = 0;
>> +	struct memory_tier *memtier;
>> +
>> +	memtier = __get_memory_tier_from_id(tier);
>> +	if (!memtier) {
>> +		ret = -EINVAL;
>> +		goto out;
>> +	}
>> +	node_set(node, memtier->nodelist);
>> +out:
>> +	return ret;
>> +}
>> +
>> +static int node_set_memory_tier(int node, int tier)
>
> Minor comment, but I don't like the name of this function as it doesn't
> always set the node to the given tier.
>
> Something like this would make it clearer the tier value is only used if
> the node isn't already assigned to a tier:
>
> static int init_node_memory_tier(int node, int default_tier)
>

Will rename to init_node_memory_tier()

-aneesh