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
.
-aneesh
