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Date: Wed, 5 Dec 2018 11:00:19 -0800 (PST)
From: David Rientjes <rientjes@google.com>
Subject: Re: [PATCH] mm/alloc: fallback to first node if the wanted node
 offline
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To: Pingfan Liu <kernelfans@gmail.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>, Mike Rapoport <rppt@linux.vnet.ibm.com>, Bjorn Helgaas <bhelgaas@google.com>, Jonathan Cameron <Jonathan.Cameron@huawei.com>

On Wed, 5 Dec 2018, Pingfan Liu wrote:

> > > And rather than using first_online_node, would next_online_node() work?
> > >
> > What is the gain? Is it for memory pressure on node0?
> >
> Maybe I got your point now.  Do you try to give a cheap assumption on
> nearest neigh of this node?
> 

It's likely better than first_online_node, but probably going to be the 
same based on the node ids that you have reported since the nodemask will 
simply wrap around back to the first node.