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Date:   Tue, 8 Mar 2022 19:56:59 +0100
From:   Oscar Salvador <osalvador@suse.de>
To:     Dave Hansen <dave.hansen@intel.com>
Cc:     "Huang, Ying" <ying.huang@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
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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.

Thanks

-- 
Oscar Salvador
SUSE Labs