Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 1 Feb 2022 06:33:38 +0000
From:   Wei Yang <richard.weiyang@gmail.com>
To:     Michal Hocko <mhocko@suse.com>
Cc:     Wei Yang <richard.weiyang@gmail.com>, akpm@linux-foundation.org,
        mgorman@techsingularity.net, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/memory_hotplug: build zonelist for managed_zone
Message-ID: <20220201063338.u4ux2jsgctuo7tex@master>
Reply-To: Wei Yang <richard.weiyang@gmail.com>
References: <20220127012023.18095-1-richard.weiyang@gmail.com>
 <YfJXoSVkQ3X5u44F@dhcp22.suse.cz>
 <20220129002628.2cwr35glahq5f5md@master>
 <Yfe48O7eBWSe0LjK@dhcp22.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Yfe48O7eBWSe0LjK@dhcp22.suse.cz>
User-Agent: NeoMutt/20170113 (1.7.2)
Precedence: bulk

On Mon, Jan 31, 2022 at 11:24:48AM +0100, Michal Hocko wrote:
>> >> This patch restore the original behavior by using the same criteria to
>> >> add a zone in zonelist during memory hotplug.
>> >
>> >Why?
>> >
>> 
>> In case we online a populated zone, but not managed. Then this zone will not
>> be in zonelist. Right?
>
>yeah. We can theoretically end up with a zone without any managed menory
>on the zonelists. But my primary question is why do we need this change?

Currently I don't see a real case for this.

>Does it fix any existing problem? Does it make the code easier to
>read/understand? Does it improve performance? Every patch should have a
>justification. Your changelog merely lists the history and then states
>the new behavior without any explanation of why that is needed or
>desired. See?

I don't have such reason now.

>-- 
>Michal Hocko
>SUSE Labs

-- 
Wei Yang
Help you, Help me