Aneesh Kumar K V <aneesh.kumar@xxxxxxxxxxxxx> writes:
> On 8/9/22 10:51 AM, Huang, Ying wrote:
>> "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
>>
>>> Also update different helpes to use NODE_DATA()->memtier. Since
>>> node specific memtier can change based on the reassignment of
>>> NUMA node to a different memory tiers, accessing NODE_DATA()->memtier
>>> needs to happen under an rcu read lock or memory_tier_lock.
>>>
>>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
>>> ---
>>> include/linux/mmzone.h | 3 +++
>>> mm/memory-tiers.c | 38 ++++++++++++++++++++++++++++++++------
>>> 2 files changed, 35 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
>>> index aab70355d64f..353812495a70 100644
>>> --- a/include/linux/mmzone.h
>>> +++ b/include/linux/mmzone.h
>>> @@ -928,6 +928,9 @@ typedef struct pglist_data {
>>> /* Per-node vmstats */
>>> struct per_cpu_nodestat __percpu *per_cpu_nodestats;
>>> atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS];
>>> +#ifdef CONFIG_NUMA
>>> + struct memory_tier __rcu *memtier;
>>> +#endif
>>> } pg_data_t;
>>>
>>> #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages)
>>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>>> index 02e514e87d5c..3778ac6a44a1 100644
>>> --- a/mm/memory-tiers.c
>>> +++ b/mm/memory-tiers.c
>>> @@ -5,6 +5,7 @@
>>> #include <linux/kobject.h>
>>> #include <linux/memory.h>
>>> #include <linux/random.h>
>>> +#include <linux/mmzone.h>
>>> #include <linux/memory-tiers.h>
>>>
>>> #include "internal.h"
>>> @@ -137,12 +138,18 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty
>>>
>>> static struct memory_tier *__node_get_memory_tier(int node)
>>> {
>>> - struct memory_dev_type *memtype;
>>> + pg_data_t *pgdat;
>>>
>>> - memtype = node_memory_types[node];
>>> - if (memtype && node_isset(node, memtype->nodes))
>>> - return memtype->memtier;
>>> - return NULL;
>>
>> After adding pgdat->memtier, it appears there's unnecessary to keep
>> memtype->memtier?
>>
>
> It do simplify find_create_memory_tier() where I use if (memtype->memtier)
> to check whether the memtype is already added to a memory tier. I could switch
> that to list_empty(memtype->tier_sibiling). But I felt the current one is much
> cleaner
I prefer "list_empty(memtype->tier_sibiling)". But I will let you to
decide.
Best Regards,
Huang, Ying
