Re: [PATCH v1 2/2] mm/damon/sysfs: use kzmalloc instead kmalloc to simplify codes

From: SeongJae Park <sj@kernel.org>
To: Xin Hao <xhao@linux.alibaba.com>
Cc: sj@kernel.org, akpm@linux-foundation.org, damon@lists.linux.dev,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/2] mm/damon/sysfs: use kzmalloc instead kmalloc to simplify codes
Date: Mon, 19 Sep 2022 17:22:51 +0000	[thread overview]
Message-ID: <20220919172251.61428-1-sj@kernel.org> (raw)
In-Reply-To: <20220919151201.66696-2-xhao@linux.alibaba.com>

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.

So, to my humble eyes, this change looks like making the code a little bit
inefficient and unclear, sorry.

Thanks,
SJ

> 
> Signed-off-by: Xin Hao <xhao@linux.alibaba.com>
> ---
>  mm/damon/sysfs.c | 15 ++-------------
>  1 file changed, 2 insertions(+), 13 deletions(-)
> 
> diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
> index b852a75b9f39..06154ece7960 100644
> --- a/mm/damon/sysfs.c
> +++ b/mm/damon/sysfs.c
> @@ -657,13 +657,7 @@ struct damon_sysfs_access_pattern {
>  static
>  struct damon_sysfs_access_pattern *damon_sysfs_access_pattern_alloc(void)
>  {
> -	struct damon_sysfs_access_pattern *access_pattern =
> -		kmalloc(sizeof(*access_pattern), GFP_KERNEL);
> -
> -	if (!access_pattern)
> -		return NULL;
> -	access_pattern->kobj = (struct kobject){};
> -	return access_pattern;
> +	return kzalloc(sizeof(struct damon_sysfs_access_pattern), GFP_KERNEL);
>  }
>  
>  static int damon_sysfs_access_pattern_add_range_dir(
> @@ -1620,12 +1614,7 @@ struct damon_sysfs_attrs {
>  
>  static struct damon_sysfs_attrs *damon_sysfs_attrs_alloc(void)
>  {
> -	struct damon_sysfs_attrs *attrs = kmalloc(sizeof(*attrs), GFP_KERNEL);
> -
> -	if (!attrs)
> -		return NULL;
> -	attrs->kobj = (struct kobject){};
> -	return attrs;
> +	return kzalloc(sizeof(struct damon_sysfs_attrs), GFP_KERNEL);
>  }
>  
>  static int damon_sysfs_attrs_add_dirs(struct damon_sysfs_attrs *attrs)
> -- 
> 2.31.0