Re: [PATCH 2/2] mm: huge_memory: refactor defrag_show() to use defrag_flags[]

["David Hildenbrand (Arm)" <david@kernel.org>]

On 3/20/26 17:05, Breno Leitao wrote:
> Replace the hardcoded if/else chain of test_bit() calls and string
> literals in defrag_show() with a loop over defrag_flags[] and
> defrag_mode_strings[] arrays introduced in the previous commit.
> 
> This makes defrag_show() consistent with defrag_store() and eliminates
> the duplicated mode name strings.
> 
> Signed-off-by: Breno Leitao <leitao@debian.org>
> ---
>  mm/huge_memory.c | 38 ++++++++++++++++++++++----------------
>  1 file changed, 22 insertions(+), 16 deletions(-)
> 
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 4843e2154038f..eaa6623fa49e2 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -447,24 +447,30 @@ static const enum transparent_hugepage_flag defrag_flags[] = {
>  static ssize_t defrag_show(struct kobject *kobj,
>  			   struct kobj_attribute *attr, char *buf)
>  {
> -	const char *output;
> +	int active = DEFRAG_NEVER;
> +	int len = 0;
> +	int i;
>  
> -	if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG,
> -		     &transparent_hugepage_flags))
> -		output = "[always] defer defer+madvise madvise never";
> -	else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG,
> -			  &transparent_hugepage_flags))
> -		output = "always [defer] defer+madvise madvise never";
> -	else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG,
> -			  &transparent_hugepage_flags))
> -		output = "always defer [defer+madvise] madvise never";
> -	else if (test_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
> -			  &transparent_hugepage_flags))
> -		output = "always defer defer+madvise [madvise] never";
> -	else
> -		output = "always defer defer+madvise madvise [never]";
> +	for (i = 0; i < ARRAY_SIZE(defrag_flags); i++) {
> +		if (test_bit(defrag_flags[i], &transparent_hugepage_flags)) {
> +			active = i;
> +			break;
> +		}
> +	}
>  
> -	return sysfs_emit(buf, "%s\n", output);
> +	for (i = 0; i < ARRAY_SIZE(defrag_mode_strings); i++) {
> +		if (i == active)
> +			len += sysfs_emit_at(buf, len, "[%s] ",
> +					     defrag_mode_strings[i]);
> +		else
> +			len += sysfs_emit_at(buf, len, "%s ",
> +					     defrag_mode_strings[i]);
> +	}
> +
> +	/* Replace trailing space with newline */
> +	buf[len - 1] = '\n';
> +
> +	return len;

The old code was certainly way easier to get. But this one here looks
good to me.

Acked-by: David Hildenbrand (Arm) <david@kernel.org>

-- 
Cheers,

David