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Subject: Re: [PATCH] memory tier: rename destroy_memory_type() to
 put_memory_type()
To:     Xiao Yang <yangx.jy@fujitsu.com>
CC:     <ying.huang@intel.com>, <nvdimm@lists.linux.dev>,
        <linux-cxl@vger.kernel.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>, <akpm@linux-foundation.org>,
        <dan.j.williams@intel.com>, <vishal.l.verma@intel.com>,
        <dave.jiang@intel.com>
References: <20230706063905.543800-1-linmiaohe@huawei.com>
 <7956e695-3eac-25ef-4412-3a0ff33e3574@fujitsu.com>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <428b3127-6b48-c19f-ae87-a1975b162e5c@huawei.com>
Date:   Thu, 6 Jul 2023 21:11:02 +0800
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On 2023/7/6 19:58, Xiao Yang wrote:
> On 2023/7/6 14:39, Miaohe Lin wrote:
>> It appears that destroy_memory_type() isn't a very good name because
>> we usually will not free the memory_type here. So rename it to a more
>> appropriate name i.e. put_memory_type().
>>
>> Suggested-by: Huang, Ying <ying.huang@intel.com>
>> Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
>> ---
>>   drivers/dax/kmem.c           | 4 ++--
>>   include/linux/memory-tiers.h | 4 ++--
>>   mm/memory-tiers.c            | 6 +++---
>>   3 files changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
>> index 898ca9505754..c57acb73e3db 100644
>> --- a/drivers/dax/kmem.c
>> +++ b/drivers/dax/kmem.c
>> @@ -264,7 +264,7 @@ static int __init dax_kmem_init(void)
>>       return rc;
>>     error_dax_driver:
>> -    destroy_memory_type(dax_slowmem_type);
>> +    put_memory_type(dax_slowmem_type);
>>   err_dax_slowmem_type:
>>       kfree_const(kmem_name);
>>       return rc;
>> @@ -275,7 +275,7 @@ static void __exit dax_kmem_exit(void)
>>       dax_driver_unregister(&device_dax_kmem_driver);
>>       if (!any_hotremove_failed)
>>           kfree_const(kmem_name);
>> -    destroy_memory_type(dax_slowmem_type);
>> +    put_memory_type(dax_slowmem_type);
>>   }
>>     MODULE_AUTHOR("Intel Corporation");
>> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
>> index fc9647b1b4f9..437441cdf78f 100644
>> --- a/include/linux/memory-tiers.h
>> +++ b/include/linux/memory-tiers.h
>> @@ -33,7 +33,7 @@ struct memory_dev_type {
>>   #ifdef CONFIG_NUMA
>>   extern bool numa_demotion_enabled;
>>   struct memory_dev_type *alloc_memory_type(int adistance);
>> -void destroy_memory_type(struct memory_dev_type *memtype);
>> +void put_memory_type(struct memory_dev_type *memtype);
>>   void init_node_memory_type(int node, struct memory_dev_type *default_type);
>>   void clear_node_memory_type(int node, struct memory_dev_type *memtype);
>>   #ifdef CONFIG_MIGRATION
>> @@ -68,7 +68,7 @@ static inline struct memory_dev_type *alloc_memory_type(int adistance)
>>       return NULL;
>>   }
>>   -static inline void destroy_memory_type(struct memory_dev_type *memtype)
>> +static inline void put_memory_type(struct memory_dev_type *memtype)
>>   {
>>     }
>> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
>> index 1719fa3bcf02..c49ab03f49b1 100644
>> --- a/mm/memory-tiers.c
>> +++ b/mm/memory-tiers.c
>> @@ -560,11 +560,11 @@ struct memory_dev_type *alloc_memory_type(int adistance)
>>   }
>>   EXPORT_SYMBOL_GPL(alloc_memory_type);
>>   -void destroy_memory_type(struct memory_dev_type *memtype)
>> +void put_memory_type(struct memory_dev_type *memtype)
>>   {
>>       kref_put(&memtype->kref, release_memtype);
>>   }
>> -EXPORT_SYMBOL_GPL(destroy_memory_type);
>> +EXPORT_SYMBOL_GPL(put_memory_type);
>>     void init_node_memory_type(int node, struct memory_dev_type *memtype)
>>   {
>> @@ -586,7 +586,7 @@ void clear_node_memory_type(int node, struct memory_dev_type *memtype)
>>        */
>>       if (!node_memory_types[node].map_count) {
>>           node_memory_types[node].memtype = NULL;
>> -        destroy_memory_type(memtype);
>> +        put_memory_type(memtype);
> Hi Maohe,
> 
> I didn't find that destroy_memory_type(memtype) is called here on mainline kernel. Did I miss something?

It's on linux-next tree:
 https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=e5bf0402b80d80b66e9765b2c160b5199a5c7d3b

> 
> Other than that, it looks good to me.
> Reviewed-by: Xiao Yang <yangx.jy@fujitsu.com>

Thanks for your review and comment.