linux-kernel - Re: [PATCH 06/10] maple_tree: Wrap the replace operation with an inline function.

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Date:   Tue, 16 May 2023 22:22:56 +0800
From:   Peng Zhang <zhangpeng.00@...edance.com>
To:     "Liam R. Howlett" <Liam.Howlett@...cle.com>
Cc:     Peng Zhang <zhangpeng.00@...edance.com>, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        maple-tree@...ts.infradead.org
Subject: Re: [PATCH 06/10] maple_tree: Wrap the replace operation with an
 inline function.



在 2023/5/16 22:16, Liam R. Howlett 写道:
> * Peng Zhang <zhangpeng.00@...edance.com> [230515 20:46]:
>>
>>
>> 在 2023/5/16 01:07, Liam R. Howlett 写道:
>>> * Peng Zhang <zhangpeng.00@...edance.com> [230515 09:18]:
>>>> To make mas_wr_modify() cleaner, wrap the replace operation with an
>>>> inline function.
>>>
>>> mas_wr_modify() is already pretty small.  Is there any reason you want
>>> this in its own function besides it looking cleaner?
>> I just want to make the four fast paths in mas_wr_modify()
>> look uniform without any functional effect.
> 
> I'd like to keep it the way it is. I think the comment stating what is
> going on is clear enough and mas_wr_modify() isn't too big.
Ok, I'll drop this patch in v3.
> 
>>>
>>>>
>>>> Signed-off-by: Peng Zhang <zhangpeng.00@...edance.com>
>>>> ---
>>>>    lib/maple_tree.c | 21 +++++++++++++++------
>>>>    1 file changed, 15 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
>>>> index 4c649d75a4923..ce695adc670ec 100644
>>>> --- a/lib/maple_tree.c
>>>> +++ b/lib/maple_tree.c
>>>> @@ -4288,6 +4288,19 @@ static inline void mas_wr_extend_null(struct ma_wr_state *wr_mas)
>>>>    	}
>>>>    }
>>>> +static inline bool mas_wr_replace(struct ma_wr_state *wr_mas)
>>>> +{
>>>> +	struct ma_state *mas = wr_mas->mas;
>>>> +
>>>> +	if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) {
>>>> +		rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);
>>>> +		if (!!wr_mas->entry ^ !!wr_mas->content)
>>>> +			mas_update_gap(mas);
>>>> +		return true;
>>>> +	}
>>>> +	return false;
>>>> +}
>>>> +
>>>>    static inline bool mas_wr_append(struct ma_wr_state *wr_mas)
>>>>    {
>>>>    	unsigned char end = wr_mas->node_end;
>>>> @@ -4347,13 +4360,9 @@ static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
>>>>    	unsigned char node_size;
>>>>    	struct ma_state *mas = wr_mas->mas;
>>>> -	/* Direct replacement */
>>>> -	if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) {
>>>> -		rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry);
>>>> -		if (!!wr_mas->entry ^ !!wr_mas->content)
>>>> -			mas_update_gap(mas);
>>>> +	/* Attempt to direct replace */
>>>> +	if (mas_wr_replace(wr_mas))
>>>>    		return;
>>>> -	}
>>>>    	/* Attempt to append */
>>>>    	node_slots = mt_slots[wr_mas->type];
>>>> -- 
>>>> 2.20.1
>>>>