2023-05-15 13:31:47

by Peng Zhang

Subject: [PATCH 08/10] maple_tree: Add comments and some minor cleanups to mas_wr_append()

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 <[email protected]>
---
lib/maple_tree.c | 52 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 39 insertions(+), 13 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 20082ef8c396c..538e49feafbe4 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4315,6 +4315,31 @@ 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
+ *
+ * Case 1:
+ * r_min r_max/end_piv
+ * +-------+-------+
+ * original range: | |offset |
+ * +-------+-------+
+ * +---+
+ * overwrite: | |
+ * +---+
+ * index last
+ * Case 2:
+ * r_min r_max/end_piv
+ * +-------+-------+
+ * original range: | |offset |
+ * +-------+-------+
+ * +---+
+ * overwrite: | |
+ * +---+
+ * index last
+ */
static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
{
unsigned char end = wr_mas->node_end;
@@ -4322,7 +4347,11 @@ 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)) {
+ /* Case 1 */
if (new_end < node_pivots)
wr_mas->pivots[new_end] = wr_mas->pivots[end];

@@ -4330,13 +4359,10 @@ 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)) {
+ /* Case 2 */
if (new_end < node_pivots)
wr_mas->pivots[new_end] = wr_mas->pivots[end];

@@ -4346,10 +4372,13 @@ 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;
}

/*
@@ -4385,12 +4414,9 @@ 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

2023-05-15 17:36:32

by Liam R. Howlett

Subject: Re: [PATCH 08/10] maple_tree: Add comments and some minor cleanups to mas_wr_append()

* Peng Zhang <[email protected]> [230515 09:18]:
> Add comment for mas_wr_append(), move mas_update_gap() into
> mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.

Sorry, no.

I won't accept cases in the comments and referencing it in the code.
I'm not making any vma_adjust() or vma_merge()-like comment blocks.

Please change Case 1/2 to "Append to start of range"/"Append to end of
range"

This path leads to chaos.

>
> Signed-off-by: Peng Zhang <[email protected]>
> ---
> lib/maple_tree.c | 52 ++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 20082ef8c396c..538e49feafbe4 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -4315,6 +4315,31 @@ 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
> + *
> + * Case 1:
> + * r_min r_max/end_piv
> + * +-------+-------+
> + * original range: | |offset |
> + * +-------+-------+
> + * +---+
> + * overwrite: | |
> + * +---+
> + * index last
> + * Case 2:
> + * r_min r_max/end_piv
> + * +-------+-------+
> + * original range: | |offset |
> + * +-------+-------+
> + * +---+
> + * overwrite: | |
> + * +---+
> + * index last
> + */
> static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
> {
> unsigned char end = wr_mas->node_end;
> @@ -4322,7 +4347,11 @@ 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)) {
> + /* Case 1 */
> if (new_end < node_pivots)
> wr_mas->pivots[new_end] = wr_mas->pivots[end];
>
> @@ -4330,13 +4359,10 @@ 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)) {
> + /* Case 2 */
> if (new_end < node_pivots)
> wr_mas->pivots[new_end] = wr_mas->pivots[end];
>
> @@ -4346,10 +4372,13 @@ 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;
> }
>
> /*
> @@ -4385,12 +4414,9 @@ 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
>

2023-05-16 10:11:37

by Peng Zhang

Subject: Re: [PATCH 08/10] maple_tree: Add comments and some minor cleanups to mas_wr_append()

在 2023/5/16 01:29, Liam R. Howlett 写道:
> * Peng Zhang <[email protected]> [230515 09:18]:
>> Add comment for mas_wr_append(), move mas_update_gap() into
>> mas_wr_append(), and other cleanups to make mas_wr_modify() cleaner.
>
> Sorry, no.
>
> I won't accept cases in the comments and referencing it in the code.
> I'm not making any vma_adjust() or vma_merge()-like comment blocks.
>
> Please change Case 1/2 to "Append to start of range"/"Append to end of
> range"
>
> This path leads to chaos.
I'll remove these comments in v2.
>
>>
>> Signed-off-by: Peng Zhang <[email protected]>
>> ---
>> lib/maple_tree.c | 52 ++++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 39 insertions(+), 13 deletions(-)
>>
>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>> index 20082ef8c396c..538e49feafbe4 100644
>> --- a/lib/maple_tree.c
>> +++ b/lib/maple_tree.c
>> @@ -4315,6 +4315,31 @@ 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
>> + *
>> + * Case 1:
>> + * r_min r_max/end_piv
>> + * +-------+-------+
>> + * original range: | |offset |
>> + * +-------+-------+
>> + * +---+
>> + * overwrite: | |
>> + * +---+
>> + * index last
>> + * Case 2:
>> + * r_min r_max/end_piv
>> + * +-------+-------+
>> + * original range: | |offset |
>> + * +-------+-------+
>> + * +---+
>> + * overwrite: | |
>> + * +---+
>> + * index last
>> + */
>> static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>> {
>> unsigned char end = wr_mas->node_end;
>> @@ -4322,7 +4347,11 @@ 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)) {
>> + /* Case 1 */
>> if (new_end < node_pivots)
>> wr_mas->pivots[new_end] = wr_mas->pivots[end];
>>
>> @@ -4330,13 +4359,10 @@ 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)) {
>> + /* Case 2 */
>> if (new_end < node_pivots)
>> wr_mas->pivots[new_end] = wr_mas->pivots[end];
>>
>> @@ -4346,10 +4372,13 @@ 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;
>> }
>>
>> /*
>> @@ -4385,12 +4414,9 @@ 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
>>
>