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Date: Mon, 9 May 2016 13:11:58 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Reza Arbab <arbab@linux.vnet.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Daniel Kiper <daniel.kiper@oracle.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Vlastimil Babka <vbabka@suse.cz>, Tang Chen <tangchen@cn.fujitsu.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        David Vrabel <david.vrabel@citrix.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        David Rientjes <rientjes@google.com>, Andrew Banman <abanman@sgi.com>,
        Chen Yucong <slaoub@gmail.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Yasunori Goto <y-goto@jp.fujitsu.com>,
        Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
        Zhang Zhen <zhenzhang.zhang@huawei.com>,
        Shaohua Li <shaohua.li@intel.com>
Subject: Re: [PATCH 0/3] memory-hotplug: improve rezoning capability
Message-Id: <20160509131158.d5429d4dba4a24c5b1aac9ca@linux-foundation.org>
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On Mon,  9 May 2016 12:53:36 -0500 Reza Arbab <arbab@linux.vnet.ibm.com> wrote:

> While it is currently possible to rezone memory when it is onlined, there are
> implicit assumptions about the zones:
> 
> * To "online_kernel" a block into ZONE_NORMAL, it must currently
>   be in ZONE_MOVABLE.
> 
> * To "online_movable" a block into ZONE_MOVABLE, it must currently
>   be in (ZONE_MOVABLE - 1).
> 
> So on powerpc, where new memory is hotplugged into ZONE_DMA, these operations
> do not work.
> 
> This patchset replaces the qualifications above with a more general
> validation of zone movement.
> 

The patches look good from a first scan.  It's late for 4.6 so I'll
queue them for 4.7-rc1, unless there are convincing reasons otherwise?

Hopefully the other memory-hotplug developers will be able to find time
to review these.