linux-kernel - Re: [PATCH] mm: remove the exporting of totalram

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Message-ID: <20190710142452.GN29695@dhcp22.suse.cz>
Date:   Wed, 10 Jul 2019 16:24:52 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Denis Efremov <efremov@...ux.com>
Cc:     Arun KS <arunks@...eaurora.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Oscar Salvador <osalvador@...e.de>,
        Pavel Tatashin <pavel.tatashin@...rosoft.com>,
        Mel Gorman <mgorman@...hsingularity.net>,
        Mike Rapoport <rppt@...ux.ibm.com>,
        Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: remove the exporting of totalram_pages

On Wed 10-07-19 17:10:31, Denis Efremov wrote:
> Previously totalram_pages was the global variable. Currently,
> totalram_pages is the static inline function from the include/linux/mm.h
> However, the function is also marked as EXPORT_SYMBOL, which is at best
> an odd combination. Because there is no point for the static inline
> function from a public header to be exported, this commit removes the
> EXPORT_SYMBOL() marking. It will be still possible to use the function in
> modules because all the symbols it depends on are exported.
> 
> Fixes: ca79b0c211af6 ("mm: convert totalram_pages and totalhigh_pages variables to atomic")
> Signed-off-by: Denis Efremov <efremov@...ux.com>

I have to confess I am not entirely sure what the export actually does in this
case. I _think_ it will simply create a symbol and the code will be same
as the static inline. But it certainly is not what we want/need.

Acked-by: Michal Hocko <mhocko@...e.com>

> ---
>  mm/page_alloc.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 8e3bc949ebcc..060303496094 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -224,8 +224,6 @@ int sysctl_lowmem_reserve_ratio[MAX_NR_ZONES] = {
>  	[ZONE_MOVABLE] = 0,
>  };
>  
> -EXPORT_SYMBOL(totalram_pages);
> -
>  static char * const zone_names[MAX_NR_ZONES] = {
>  #ifdef CONFIG_ZONE_DMA
>  	 "DMA",
> -- 
> 2.21.0

-- 
Michal Hocko
SUSE Labs