On 7/26/22 9:33 AM, Huang, Ying wrote:
> "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
>
>> If the new NUMA node onlined doesn't have a performance level assigned,
>> the kernel adds the NUMA node to default memory tier.
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
>> ---
>> include/linux/memory-tiers.h | 1 +
>> mm/memory-tiers.c | 75 ++++++++++++++++++++++++++++++++++++
>> 2 files changed, 76 insertions(+)
>>
>> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
>> index ef380a39db3a..3d5f14d57ae6 100644
>> --- a/include/linux/memory-tiers.h
>> +++ b/include/linux/memory-tiers.h
>> @@ -14,6 +14,7 @@
>> #define MEMTIER_PERF_LEVEL_DRAM (1 << (MEMTIER_CHUNK_BITS + 2))
>> /* leave one tier below this slow pmem */
>> #define MEMTIER_PERF_LEVEL_PMEM (1 << MEMTIER_CHUNK_BITS)
>> +#define MEMTIER_HOTPLUG_PRIO 100
>>
>> extern bool numa_demotion_enabled;
>>
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> index 41a21cc5ae55..cc3a47ec18e4 100644
>> --- a/mm/memory-tiers.c
>> +++ b/mm/memory-tiers.c
>> @@ -5,6 +5,7 @@
>> #include <linux/lockdep.h>
>> #include <linux/moduleparam.h>
>> #include <linux/node.h>
>> +#include <linux/memory.h>
>> #include <linux/memory-tiers.h>
>>
>> struct memory_tier {
>> @@ -64,6 +65,78 @@ static struct memory_tier *find_create_memory_tier(unsigned int perf_level)
>> return new_memtier;
>> }
>>
>> +static struct memory_tier *__node_get_memory_tier(int node)
>> +{
>> + struct memory_tier *memtier;
>> +
>> + list_for_each_entry(memtier, &memory_tiers, list) {
>> + if (node_isset(node, memtier->nodelist))
>> + return memtier;
>> + }
>> + return NULL;
>> +}
>> +
>> +static void init_node_memory_tier(int node)
>
> set_node_memory_tier()?
That was done based on feedback from Alistair
https://lore.kernel.org/linux-mm/87h73iapg1.fsf@nvdebian.thelocal
>
>> +{
>> + int perf_level;
>> + struct memory_tier *memtier;
>> +
>> + mutex_lock(&memory_tier_lock);
>> +
>> + memtier = __node_get_memory_tier(node);
>> + if (!memtier) {
>> + perf_level = node_devices[node]->perf_level;
>> + memtier = find_create_memory_tier(perf_level);
>> + node_set(node, memtier->nodelist);
>> + }
>> + mutex_unlock(&memory_tier_lock);
>> +}
>> +
>> +static void clear_node_memory_tier(int node)
>> +{
>> + struct memory_tier *memtier;
>> +
>> + mutex_lock(&memory_tier_lock);
>> + memtier = __node_get_memory_tier(node);
>> + if (memtier)
>> + node_clear(node, memtier->nodelist);
>
> When memtier->nodelist becomes empty, we need to free memtier?
>
>> + mutex_unlock(&memory_tier_lock);
>> +}
>> +
>> +/*
>> + * This runs whether reclaim-based migration is enabled or not,
>> + * which ensures that the user can turn reclaim-based migration
>> + * at any time without needing to recalculate migration targets.
>> + */
>
> The comments doesn't apply here.
>
>> +static int __meminit migrate_on_reclaim_callback(struct notifier_block *self,
>> + unsigned long action, void *_arg)
>
> Now we are building memory tiers instead of working on demotion. So I
> think we should rename the function to memtier_hotplug_callback().
>
>> +{
>> + struct memory_notify *arg = _arg;
>> +
>> + /*
>> + * Only update the node migration order when a node is
>> + * changing status, like online->offline.
>> + */
>> + if (arg->status_change_nid < 0)
>> + return notifier_from_errno(0);
>> +
>> + switch (action) {
>> + case MEM_OFFLINE:
>> + clear_node_memory_tier(arg->status_change_nid);
>> + break;
>> + case MEM_ONLINE:
>> + init_node_memory_tier(arg->status_change_nid);
>> + break;
>> + }
>> +
>> + return notifier_from_errno(0);
>> +}
>> +
>> +static void __init migrate_on_reclaim_init(void)
>> +{
>> + hotplug_memory_notifier(migrate_on_reclaim_callback, MEMTIER_HOTPLUG_PRIO);
>> +}
>
> I suggest to call hotplug_memory_notifier() in memory_tier_init()
> directly. We are not working on demotion here.
>
>> +
>> static int __init memory_tier_init(void)
>> {
>> int node;
>> @@ -96,6 +169,8 @@ static int __init memory_tier_init(void)
>> node_property->perf_level = default_memtier_perf_level;
>> }
>> mutex_unlock(&memory_tier_lock);
>> +
>> + migrate_on_reclaim_init();
>> return 0;
>> }
>> subsys_initcall(memory_tier_init);
>
> Best Regards,
> Huang, Ying
Will update the patch in next iteration to take care of other feedback.
Thanks
-aneesh
