linux-kernel - Re: [PATCH] mm/mmap: use SZ

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Message-ID: <Zbi9OyG9kcldGyJ1@kernel.org>
Date: Tue, 30 Jan 2024 11:11:23 +0200
From: Mike Rapoport <rppt@...nel.org>
To: Yajun Deng <yajun.deng@...ux.dev>
Cc: akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm/mmap: use SZ_{8M, 128M} helper macro

On Fri, Jan 26, 2024 at 04:59:05PM +0800, Yajun Deng wrote:
> Use SZ_{8M, 128M} macro intead of the number in init_user_reserve and
> reserve_mem_notifier.
> 
> Signed-off-by: Yajun Deng <yajun.deng@...ux.dev>
> ---
>  mm/mmap.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 476de5daf598..f90924b2a6d2 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -3845,7 +3845,7 @@ static int init_user_reserve(void)
>  
>  	free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
>  
> -	sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
> +	sysctl_user_reserve_kbytes = min(free_kbytes / 32, SZ_128M);

(1UL << 17) != SZ_128M

>  	return 0;
>  }
>  subsys_initcall(init_user_reserve);
> @@ -3866,7 +3866,7 @@ static int init_admin_reserve(void)
>  
>  	free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
>  
> -	sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
> +	sysctl_admin_reserve_kbytes = min(free_kbytes / 32, SZ_8M);
>  	return 0;
>  }
>  subsys_initcall(init_admin_reserve);
> @@ -3898,12 +3898,12 @@ static int reserve_mem_notifier(struct notifier_block *nb,
>  	case MEM_ONLINE:
>  		/* Default max is 128MB. Leave alone if modified by operator. */
>  		tmp = sysctl_user_reserve_kbytes;
> -		if (0 < tmp && tmp < (1UL << 17))
> +		if (tmp > 0 && tmp < SZ_128M)
>  			init_user_reserve();
>  
>  		/* Default max is 8MB.  Leave alone if modified by operator. */
>  		tmp = sysctl_admin_reserve_kbytes;
> -		if (0 < tmp && tmp < (1UL << 13))
> +		if (tmp > 0 && tmp < SZ_8M)

(1UL << 13) != SZ_8M

>  			init_admin_reserve();
>  
>  		break;
> -- 
> 2.25.1
> 
> 

-- 
Sincerely yours,
Mike.