linux-kernel - Re: [PATCH 3/5] mm/memory_hotplug: Tidy up node_states_clear

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Message-ID: <73bf94f3-d53b-0123-0b1e-86fd00f66694@microsoft.com>
Date:   Thu, 20 Sep 2018 23:40:39 +0000
From:   Pasha Tatashin <Pavel.Tatashin@...rosoft.com>
To:     Oscar Salvador <osalvador@...hadventures.net>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
CC:     "mhocko@...e.com" <mhocko@...e.com>,
        "dan.j.williams@...el.com" <dan.j.williams@...el.com>,
        "david@...hat.com" <david@...hat.com>,
        "Jonathan.Cameron@...wei.com" <Jonathan.Cameron@...wei.com>,
        "yasu.isimatu@...il.com" <yasu.isimatu@...il.com>,
        "malat@...ian.org" <malat@...ian.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Oscar Salvador <osalvador@...e.de>
Subject: Re: [PATCH 3/5] mm/memory_hotplug: Tidy up node_states_clear_node



On 9/19/18 6:08 AM, Oscar Salvador wrote:
> From: Oscar Salvador <osalvador@...e.de>
> 
> node_states_clear has the following if statements:
> 
> if ((N_MEMORY != N_NORMAL_MEMORY) &&
>     (arg->status_change_nid_high >= 0))
>         ...
> 
> if ((N_MEMORY != N_HIGH_MEMORY) &&
>     (arg->status_change_nid >= 0))
>         ...
> 
> N_MEMORY can never be equal to neither N_NORMAL_MEMORY nor
> N_HIGH_MEMORY.
> 
> Similar problem was found in [1].
> Since this is wrong, let us get rid of it.
> 
> [1] https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fpatch%2F10579155%2F&amp;data=02%7C01%7CPavel.Tatashin%40microsoft.com%7C1e31e6a5c8754abe0b4608d61e17e01c%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C636729485241367584&amp;sdata=ztkPNyRIv2c0j5lrujwGM%2FrD5in6G7AvvdqxVXCzwGs%3D&amp;reserved=0
> 
> Signed-off-by: Oscar Salvador <osalvador@...e.de>

Reviewed-by: Pavel Tatashin <pavel.tatashin@...rosoft.com>

> ---
>  mm/memory_hotplug.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index c2c7359bd0a7..131c08106d54 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1590,12 +1590,10 @@ static void node_states_clear_node(int node, struct memory_notify *arg)
>  	if (arg->status_change_nid_normal >= 0)
>  		node_clear_state(node, N_NORMAL_MEMORY);
>  
> -	if ((N_MEMORY != N_NORMAL_MEMORY) &&
> -	    (arg->status_change_nid_high >= 0))
> +	if (arg->status_change_nid_high >= 0)
>  		node_clear_state(node, N_HIGH_MEMORY);
>  
> -	if ((N_MEMORY != N_HIGH_MEMORY) &&
> -	    (arg->status_change_nid >= 0))
> +	if (arg->status_change_nid >= 0)
>  		node_clear_state(node, N_MEMORY);
>  }
>  
>