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Date: Sat, 26 Sep 2015 17:35:38 +0800
From: Tang Chen <tangchen@cn.fujitsu.com>
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To: Christoph Lameter <cl@linux.com>, Tejun Heo <tj@kernel.org>
CC: <jiang.liu@linux.intel.com>, <mika.j.penttila@gmail.com>,
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Subject: Re: [PATCH v2 3/7] x86, gfp: Cache best near node for memory allocation.
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Hi, Christoph, tj,

On 09/11/2015 08:14 AM, Christoph Lameter wrote:
> On Thu, 10 Sep 2015, Tejun Heo wrote:
>
>>> Why not just update node_data[]->node_zonelist in the first place?
>>> Also, what's the synchronization rule here?  How are allocators
>>> synchronized against node hot [un]plugs?
>> Also, shouldn't kmalloc_node() or any public allocator fall back
>> automatically to a near node w/o GFP_THISNODE?  Why is this failing at
>> all?  I get that cpu id -> node id mapping changing messes up the
>> locality but allocations shouldn't fail, right?

Yes. That is the reason we are getting near online node here.

> Yes that should occur in the absence of other constraints (mempolicies,
> cpusets, cgroups, allocation type). If the constraints do not allow an
> allocation then the allocation will fail.
>
> Also: Are the zonelists setup the right way?

zonelist will be rebuilt in __offline_pages() when the zone is not 
populated any more.

Thanks.