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Message-ID: <e106ee62-8b4b-59bc-d7ec-510c0c75c30a@gmail.com>
Date:   Mon, 31 Jul 2023 19:40:16 +0800
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Subject: Re: [PATCH 03/11] maple_tree: Add some helper functions
To:     "Liam R. Howlett" <Liam.Howlett@Oracle.com>
References: <20230726080916.17454-1-zhangpeng.00@bytedance.com>
 <20230726080916.17454-4-zhangpeng.00@bytedance.com>
 <20230726150252.x56owgz3ikujzicu@revolver>
Cc:     peterz@infradead.org, mathieu.desnoyers@efficios.com,
        brauner@kernel.org, Peng Zhang <zhangpeng.00@bytedance.com>,
        surenb@google.com, linux-kernel@vger.kernel.org, npiggin@gmail.com,
        linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
        akpm@linux-foundation.org, corbet@lwn.net, willy@infradead.org,
        linux-mm@kvack.org, avagin@gmail.com, michael.christie@oracle.com
From:   Peng Zhang <perlyzhang@gmail.com>
In-Reply-To: <20230726150252.x56owgz3ikujzicu@revolver>
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Precedence: bulk


在 2023/7/26 23:02, Liam R. Howlett 写道:
> * Peng Zhang <zhangpeng.00@bytedance.com> [230726 04:10]:
>> Add some helper functions so that their parameters are maple node
>> instead of maple enode, these functions will be used later.
>>
>> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
>> ---
>>   lib/maple_tree.c | 71 +++++++++++++++++++++++++++++++++++++-----------
>>   1 file changed, 55 insertions(+), 16 deletions(-)
>>
>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>> index e0e9a87bdb43..da3a2fb405c0 100644
>> --- a/lib/maple_tree.c
>> +++ b/lib/maple_tree.c
>> @@ -164,6 +164,11 @@ static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes)
>>   	return kmem_cache_alloc_bulk(maple_node_cache, gfp, size, nodes);
>>   }
>>   
>> +static inline void mt_free_one(struct maple_node *node)
>> +{
>> +	kmem_cache_free(maple_node_cache, node);
>> +}
>> +
> 
> There is a place in mas_destroy() that could use this if it is added.
I will make changes accordingly. It's not done here because it doesn't
seem to be relevant to the theme of this patchset.
> 
>>   static inline void mt_free_bulk(size_t size, void __rcu **nodes)
>>   {
>>   	kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes);
>> @@ -432,18 +437,18 @@ static inline unsigned long mte_parent_slot_mask(unsigned long parent)
>>   }
>>   
>>   /*
>> - * mas_parent_type() - Return the maple_type of the parent from the stored
>> - * parent type.
>> - * @mas: The maple state
>> - * @enode: The maple_enode to extract the parent's enum
>> + * ma_parent_type() - Return the maple_type of the parent from the stored parent
>> + * type.
>> + * @mt: The maple tree
>> + * @node: The maple_node to extract the parent's enum
>>    * Return: The node->parent maple_type
>>    */
>>   static inline
>> -enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode)
>> +enum maple_type ma_parent_type(struct maple_tree *mt, struct maple_node *node)
> 
> I was trying to keep ma_* prefix to mean the first argument is
> maple_node and mt_* to mean maple_tree.  I wasn't entirely successful
> with this and I do see why you want to use ma_, but maybe reverse the
> arguments here?
I just think it is redundant to construct maple enode through
node->parent in order to adapt the parameters of mte_*. So ma_* are
introduced to avoid meaningless construction.

> 
>>   {
>>   	unsigned long p_type;
>>   
>> -	p_type = (unsigned long)mte_to_node(enode)->parent;
>> +	p_type = (unsigned long)node->parent;
>>   	if (WARN_ON(p_type & MAPLE_PARENT_ROOT))
>>   		return 0;
>>   
>> @@ -451,7 +456,7 @@ enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode)
>>   	p_type &= ~mte_parent_slot_mask(p_type);
>>   	switch (p_type) {
>>   	case MAPLE_PARENT_RANGE64: /* or MAPLE_PARENT_ARANGE64 */
>> -		if (mt_is_alloc(mas->tree))
>> +		if (mt_is_alloc(mt))
>>   			return maple_arange_64;
>>   		return maple_range_64;
>>   	}
>> @@ -459,6 +464,19 @@ enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode)
>>   	return 0;
>>   }
>>   
>> +/*
>> + * mas_parent_type() - Return the maple_type of the parent from the stored
>> + * parent type.
>> + * @mas: The maple state
>> + * @enode: The maple_enode to extract the parent's enum
>> + * Return: The node->parent maple_type
>> + */
>> +static inline
>> +enum maple_type mas_parent_type(struct ma_state *mas, struct maple_enode *enode)
>> +{
>> +	return ma_parent_type(mas->tree, mte_to_node(enode));
>> +}
>> +
>>   /*
>>    * mas_set_parent() - Set the parent node and encode the slot
>>    * @enode: The encoded maple node.
>> @@ -499,14 +517,14 @@ void mas_set_parent(struct ma_state *mas, struct maple_enode *enode,
>>   }
>>   
>>   /*
>> - * mte_parent_slot() - get the parent slot of @enode.
>> - * @enode: The encoded maple node.
>> + * ma_parent_slot() - get the parent slot of @node.
>> + * @node: The maple node.
>>    *
>> - * Return: The slot in the parent node where @enode resides.
>> + * Return: The slot in the parent node where @node resides.
>>    */
>> -static inline unsigned int mte_parent_slot(const struct maple_enode *enode)
>> +static inline unsigned int ma_parent_slot(const struct maple_node *node)
>>   {
>> -	unsigned long val = (unsigned long)mte_to_node(enode)->parent;
>> +	unsigned long val = (unsigned long)node->parent;
>>   
>>   	if (val & MA_ROOT_PARENT)
>>   		return 0;
>> @@ -519,15 +537,36 @@ static inline unsigned int mte_parent_slot(const struct maple_enode *enode)
>>   }
>>   
>>   /*
>> - * mte_parent() - Get the parent of @node.
>> - * @node: The encoded maple node.
>> + * mte_parent_slot() - get the parent slot of @enode.
>> + * @enode: The encoded maple node.
>> + *
>> + * Return: The slot in the parent node where @enode resides.
>> + */
>> +static inline unsigned int mte_parent_slot(const struct maple_enode *enode)
>> +{
>> +	return ma_parent_slot(mte_to_node(enode));
>> +}
>> +
>> +/*
>> + * ma_parent() - Get the parent of @node.
>> + * @node: The maple node.
>> + *
>> + * Return: The parent maple node.
>> + */
>> +static inline struct maple_node *ma_parent(const struct maple_node *node)
> 
> I had a lot of these helpers before, but they eventually became used so
> little that I dropped them.
Just for not wanting to construct maple enode. It's not really a
problem.
> 
>> +{
>> +	return (void *)((unsigned long)(node->parent) & ~MAPLE_NODE_MASK);
>> +}
>> +
>> +/*
>> + * mte_parent() - Get the parent of @enode.
>> + * @enode: The encoded maple node.
>>    *
>>    * Return: The parent maple node.
>>    */
>>   static inline struct maple_node *mte_parent(const struct maple_enode *enode)
>>   {
>> -	return (void *)((unsigned long)
>> -			(mte_to_node(enode)->parent) & ~MAPLE_NODE_MASK);
>> +	return ma_parent(mte_to_node(enode));
>>   }
>>   
>>   /*
>> -- 
>> 2.20.1
>>