diff mbox series

[v2,07/10] maple_tree: Add comments and some minor cleanups to mas_wr_append()

Message ID 20230517085809.86522-8-zhangpeng.00@bytedance.com
State New
Headers
Series Clean ups for maple tree |

Commit Message

Peng Zhang May 17, 2023, 8:58 a.m. UTC 
  Add comment for mas_wr_append(), move mas_update_gap() into
mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.

Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
---
 lib/maple_tree.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

Comments

Liam R. Howlett May 17, 2023, 7:33 p.m. UTC | #1 
* Peng Zhang <zhangpeng.00@bytedance.com> [230517 04:59]:
> Add comment for mas_wr_append(), move mas_update_gap() into
> mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.
> 
> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
> ---
>  lib/maple_tree.c | 33 ++++++++++++++++++++-------------
>  1 file changed, 20 insertions(+), 13 deletions(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 3b9d227f3d7d..bbe4c6f2858c 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -4308,6 +4308,12 @@ static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
>  	return new_end;
>  }
>  
> +/*
> + * mas_wr_append: Attempt to append
> + * @wr_mas: the maple write state
> + *
> + * Return: True if appended, false otherwise
> + */
>  static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>  {
>  	unsigned char end = wr_mas->node_end;
> @@ -4315,7 +4321,11 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>  	struct ma_state *mas = wr_mas->mas;
>  	unsigned char node_pivots = mt_pivots[wr_mas->type];
>  
> +	if (!(mas->offset == wr_mas->node_end))
> +		return false;
> +
>  	if ((mas->index != wr_mas->r_min) && (mas->last == wr_mas->r_max)) {
> +		/* Append to end of range */
>  		if (new_end < node_pivots)
>  			wr_mas->pivots[new_end] = wr_mas->pivots[end];
>  
> @@ -4323,13 +4333,10 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>  			ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end);
>  
>  		rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->entry);
> -		mas->offset = new_end;
>  		wr_mas->pivots[end] = mas->index - 1;
> -
> -		return true;
> -	}
> -
> -	if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
> +		mas->offset = new_end;
> +	} else if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
> +		/* Append to start of range */
>  		if (new_end < node_pivots)
>  			wr_mas->pivots[new_end] = wr_mas->pivots[end];
>  
> @@ -4339,10 +4346,13 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>  
>  		wr_mas->pivots[end] = mas->last;
>  		rcu_assign_pointer(wr_mas->slots[end], wr_mas->entry);
> -		return true;
> +	} else {
> +		return false;

I don't think we can get here with your changes, what do you think?  If
so, we can move the metadata setting to the outside of the if/else.  I
checked by adding a BUG_ON() and the test code never gets here.

My thinking is, we know offset == node_end and new_end == node_end + 1..
so we must be inserting into the last slot and only adding one entry.

>  	}
>  
> -	return false;
> +	if (!wr_mas->content || !wr_mas->entry)
> +		mas_update_gap(mas);
> +	return  true;
>  }
>  
>  /*
> @@ -4382,12 +4392,9 @@ static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
>  	if (new_end >= mt_slots[wr_mas->type])
>  		goto slow_path;
>  
> -	if (wr_mas->entry && (wr_mas->node_end < mt_slots[wr_mas->type] - 1) &&
> -	    (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) {
> -		if (!wr_mas->content || !wr_mas->entry)
> -			mas_update_gap(mas);
> +	/* Attempt to append */
> +	if (new_end == wr_mas->node_end + 1 && mas_wr_append(wr_mas))
>  		return;
> -	}
>  
>  	if ((wr_mas->offset_end - mas->offset <= 1) && mas_wr_slot_store(wr_mas))
>  		return;
> -- 
> 2.20.1
>
Peng Zhang May 18, 2023, 9:27 a.m. UTC | #2 
在 2023/5/18 03:33, Liam R. Howlett 写道:
> * Peng Zhang <zhangpeng.00@bytedance.com> [230517 04:59]:
>> Add comment for mas_wr_append(), move mas_update_gap() into
>> mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.
>>
>> Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
>> ---
>>   lib/maple_tree.c | 33 ++++++++++++++++++++-------------
>>   1 file changed, 20 insertions(+), 13 deletions(-)
>>
>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>> index 3b9d227f3d7d..bbe4c6f2858c 100644
>> --- a/lib/maple_tree.c
>> +++ b/lib/maple_tree.c
>> @@ -4308,6 +4308,12 @@ static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
>>   	return new_end;
>>   }
>>   
>> +/*
>> + * mas_wr_append: Attempt to append
>> + * @wr_mas: the maple write state
>> + *
>> + * Return: True if appended, false otherwise
>> + */
>>   static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>>   {
>>   	unsigned char end = wr_mas->node_end;
>> @@ -4315,7 +4321,11 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>>   	struct ma_state *mas = wr_mas->mas;
>>   	unsigned char node_pivots = mt_pivots[wr_mas->type];
>>   
>> +	if (!(mas->offset == wr_mas->node_end))
>> +		return false;
>> +
>>   	if ((mas->index != wr_mas->r_min) && (mas->last == wr_mas->r_max)) {
>> +		/* Append to end of range */
>>   		if (new_end < node_pivots)
>>   			wr_mas->pivots[new_end] = wr_mas->pivots[end];
>>   
>> @@ -4323,13 +4333,10 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>>   			ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end);
>>   
>>   		rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->entry);
>> -		mas->offset = new_end;
>>   		wr_mas->pivots[end] = mas->index - 1;
>> -
>> -		return true;
>> -	}
>> -
>> -	if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
>> +		mas->offset = new_end;
>> +	} else if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
>> +		/* Append to start of range */
>>   		if (new_end < node_pivots)
>>   			wr_mas->pivots[new_end] = wr_mas->pivots[end];
>>   
>> @@ -4339,10 +4346,13 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>>   
>>   		wr_mas->pivots[end] = mas->last;
>>   		rcu_assign_pointer(wr_mas->slots[end], wr_mas->entry);
>> -		return true;
>> +	} else {
>> +		return false;
> 
> I don't think we can get here with your changes, what do you think?  If
> so, we can move the metadata setting to the outside of the if/else.  I
> checked by adding a BUG_ON() and the test code never gets here.
> 
> My thinking is, we know offset == node_end and new_end == node_end + 1..
> so we must be inserting into the last slot and only adding one entry.
Yes, I'll address this in v3. Thanks.
> 
>>   	}
>>   
>> -	return false;
>> +	if (!wr_mas->content || !wr_mas->entry)
>> +		mas_update_gap(mas);
>> +	return  true;
>>   }
>>   
>>   /*
>> @@ -4382,12 +4392,9 @@ static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
>>   	if (new_end >= mt_slots[wr_mas->type])
>>   		goto slow_path;
>>   
>> -	if (wr_mas->entry && (wr_mas->node_end < mt_slots[wr_mas->type] - 1) &&
>> -	    (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) {
>> -		if (!wr_mas->content || !wr_mas->entry)
>> -			mas_update_gap(mas);
>> +	/* Attempt to append */
>> +	if (new_end == wr_mas->node_end + 1 && mas_wr_append(wr_mas))
>>   		return;
>> -	}
>>   
>>   	if ((wr_mas->offset_end - mas->offset <= 1) && mas_wr_slot_store(wr_mas))
>>   		return;
>> -- 
>> 2.20.1
>>
diff mbox series

Patch

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 3b9d227f3d7d..bbe4c6f2858c 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4308,6 +4308,12 @@  static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
 	return new_end;
 }
 
+/*
+ * mas_wr_append: Attempt to append
+ * @wr_mas: the maple write state
+ *
+ * Return: True if appended, false otherwise
+ */
 static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
 {
 	unsigned char end = wr_mas->node_end;
@@ -4315,7 +4321,11 @@  static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
 	struct ma_state *mas = wr_mas->mas;
 	unsigned char node_pivots = mt_pivots[wr_mas->type];
 
+	if (!(mas->offset == wr_mas->node_end))
+		return false;
+
 	if ((mas->index != wr_mas->r_min) && (mas->last == wr_mas->r_max)) {
+		/* Append to end of range */
 		if (new_end < node_pivots)
 			wr_mas->pivots[new_end] = wr_mas->pivots[end];
 
@@ -4323,13 +4333,10 @@  static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
 			ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end);
 
 		rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->entry);
-		mas->offset = new_end;
 		wr_mas->pivots[end] = mas->index - 1;
-
-		return true;
-	}
-
-	if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
+		mas->offset = new_end;
+	} else if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) {
+		/* Append to start of range */
 		if (new_end < node_pivots)
 			wr_mas->pivots[new_end] = wr_mas->pivots[end];
 
@@ -4339,10 +4346,13 @@  static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
 
 		wr_mas->pivots[end] = mas->last;
 		rcu_assign_pointer(wr_mas->slots[end], wr_mas->entry);
-		return true;
+	} else {
+		return false;
 	}
 
-	return false;
+	if (!wr_mas->content || !wr_mas->entry)
+		mas_update_gap(mas);
+	return  true;
 }
 
 /*
@@ -4382,12 +4392,9 @@  static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
 	if (new_end >= mt_slots[wr_mas->type])
 		goto slow_path;
 
-	if (wr_mas->entry && (wr_mas->node_end < mt_slots[wr_mas->type] - 1) &&
-	    (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) {
-		if (!wr_mas->content || !wr_mas->entry)
-			mas_update_gap(mas);
+	/* Attempt to append */
+	if (new_end == wr_mas->node_end + 1 && mas_wr_append(wr_mas))
 		return;
-	}
 
 	if ((wr_mas->offset_end - mas->offset <= 1) && mas_wr_slot_store(wr_mas))
 		return;