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From:   "Huang, Ying" <ying.huang@intel.com>
To:     Oscar Salvador <osalvador@suse.de>
Cc:     Dave Hansen <dave.hansen@intel.com>,
        Abhishek Goel <huntbag@linux.vnet.ibm.com>,
        Dave Hansen <dave.hansen@linux.intel.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Zi Yan <ziy@nvidia.com>,
        David Hildenbrand <david@redhat.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH -V11 2/9] mm/migrate: update node demotion order on
 hotplug events
References: <20210721063926.3024591-1-ying.huang@intel.com>
        <20210721063926.3024591-2-ying.huang@intel.com>
        <eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com>
        <f5edb9dc-8b25-47c2-9905-09e88e41861b@intel.com>
        <4e8067e1-0574-c9d2-9d6c-d676d32071bd@linux.vnet.ibm.com>
        <87pmnb3ccr.fsf@yhuang6-desk2.ccr.corp.intel.com>
        <YicvnkVODh5qbxTC@localhost.localdomain>
        <86383ac9-e5f2-1a2e-dd19-02e39714a3fd@intel.com>
        <Yiem+4YbComC0EGC@localhost.localdomain>
Date:   Wed, 09 Mar 2022 08:29:40 +0800
In-Reply-To: <Yiem+4YbComC0EGC@localhost.localdomain> (Oscar Salvador's
        message of "Tue, 8 Mar 2022 19:56:59 +0100")
Message-ID: <87k0d4ge8b.fsf@yhuang6-desk2.ccr.corp.intel.com>
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Oscar Salvador <osalvador@suse.de> writes:

> On Tue, Mar 08, 2022 at 09:07:20AM -0800, Dave Hansen wrote:
>> On 3/8/22 02:27, Oscar Salvador wrote:
>> > @@ -2043,7 +2044,12 @@ static void __init init_cpu_node_state(void)
>> >  static int vmstat_cpu_online(unsigned int cpu)
>> >  {
>> >  	refresh_zone_stat_thresholds();
>> > -	node_set_state(cpu_to_node(cpu), N_CPU);
>> > +
>> > +	if (!node_state(cpu_to_node(cpu), N_CPU)) {
>> > +		node_set_state(cpu_to_node(cpu), N_CPU);
>> > +		set_migration_target_nodes();
>> > +	}
>> > +
>> >  	return 0;
>> >  }
>> > 
>> > @@ -2066,6 +2072,8 @@ static int vmstat_cpu_dead(unsigned int cpu)
>> >  		return 0;
>> > 
>> >  	node_clear_state(node, N_CPU);
>> > +	set_migration_target_nodes();
>> > +
>> >  	return 0;
>> >  }
>> 
>> Yeah, those callbacks do look like they're reinventing the wheel.  This
>> is a much more direct way of doing it.
>
> Then let me play a bit more with it and I can cook a patch unless
> someone feels strong against it.

This looks good to me, Thanks!

Best Regards,
Huang, Ying