Re: [PATCH] mm/khugepaged: replace mutex_lock/mutex_unlock usage with guard macro

[Dev Jain]

On 27/07/26 11:41 pm, Jakov Novak wrote:
> Currently, khugepaged locks the khugepaged_mutex in two functions:
> start_stop_khugepaged and khugepaged_min_free_kbytes_update. Remove
> mutex_lock/mutex_unlock usage in these functions and replace it with the
> guard macro. This makes the code more readable (removing a goto statement)
> and makes it harder to introduce bugs in the future.
> No functional changes introduced.
> 
> Signed-off-by: Jakov Novak <jakovnovak30@xxxxxxxxx>
> ---

Thanks.

Reviewed-by: Dev Jain <dev.jain@xxxxxxx>

>  mm/khugepaged.c | 9 +++------
>  1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index 617bca76db49..c583867f2e7a 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -3113,7 +3113,7 @@ int start_stop_khugepaged(void)
>  {
>  	int err = 0;
>  
> -	mutex_lock(&khugepaged_mutex);
> +	guard(mutex)(&khugepaged_mutex);
>  	if (hugepage_enabled()) {
>  		if (!khugepaged_thread)
>  			khugepaged_thread = kthread_run(khugepaged, NULL,
> @@ -3122,7 +3122,7 @@ int start_stop_khugepaged(void)
>  			pr_err("khugepaged: kthread_run(khugepaged) failed\n");
>  			err = PTR_ERR(khugepaged_thread);
>  			khugepaged_thread = NULL;
> -			goto fail;
> +			return err;
>  		}
>  
>  		if (!list_empty(&khugepaged_scan.mm_head))
> @@ -3132,17 +3132,14 @@ int start_stop_khugepaged(void)
>  		khugepaged_thread = NULL;
>  	}
>  	set_recommended_min_free_kbytes();
> -fail:
> -	mutex_unlock(&khugepaged_mutex);
>  	return err;
>  }
>  
>  void khugepaged_min_free_kbytes_update(void)
>  {
> -	mutex_lock(&khugepaged_mutex);
> +	guard(mutex)(&khugepaged_mutex);
>  	if (hugepage_enabled() && khugepaged_thread)
>  		set_recommended_min_free_kbytes();
> -	mutex_unlock(&khugepaged_mutex);
>  }
>  
>  bool current_is_khugepaged(void)