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Message-ID: <09ddb8f0-9ea3-2dd0-fa77-430ff3380f85@linux.alibaba.com>
Date:   Wed, 21 Sep 2022 13:20:21 +0800
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Subject: Re: [PATCH v1 2/2] mm/damon/sysfs: use kzmalloc instead kmalloc to
 simplify codes
To:     SeongJae Park <sj@kernel.org>
Cc:     akpm@linux-foundation.org, damon@lists.linux.dev,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20220920162542.52554-1-sj@kernel.org>
From:   haoxin <xhao@linux.alibaba.com>
In-Reply-To: <20220920162542.52554-1-sj@kernel.org>
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在 2022/9/21 上午12:25, SeongJae Park 写道:
> Hi Xin,
>
> On Tue, 20 Sep 2022 09:58:41 +0800 haoxin <xhao@linux.alibaba.com> wrote:
>
>> 在 2022/9/20 上午1:22, SeongJae Park 写道:
>>> On Mon, 19 Sep 2022 23:12:01 +0800 Xin Hao <xhao@linux.alibaba.com> wrote:
>>>
>>>> In damon_sysfs_access_pattern_alloc() adn damon_sysfs_attrs_alloc(),
>>>> we can use kzmalloc to alloc instance of the related structs, This makes
>>>> the function code much cleaner.
>>> This definitely makes the code cleaner, thank you.  But, the initial intent of
>>> the code is to initialize the fiedls that really need to be initialized at the
>>> point, for the efficiency and also for making it clear which field is needed to
>>> be initialized to what value here.  It's also intended to make readers wonder
>>> about where and how the remaining fields are initialized.
>> Maybe the other func like damon_sysfs_kdamonds_alloc() also need to do
>> like this, you can see it return directly by
>>
>> kzalloc.
>>
>> static struct damon_sysfs_kdamonds *damon_sysfs_kdamonds_alloc(void)
>> {
>>               return kzalloc(sizeof(struct damon_sysfs_kdamonds),
>> GFP_KERNEL);
>> }
> In this case, all the fields of the struct need to be initialized as zero.
> That's why we use kzalloc() there.
>
> Of course, my opinion is not a static and concrete rule, but changing mind.
> And obviously everyone makes many mistakes and DAMON code has many rooms for
> improvement.
Understand your concern,  at least, there is no point in simplifying the 
code too mush if we are ignoring its readability.
>   I really appreciate for your greatful efforts for that.  But, at
> least in this case, I think it doesn't really need the change at the moment,
> IMHO.
>
>
> Thanks,
> SJ
>
> [...]