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Subject: Re: [PATCH] memory-hotplug: Fix bad area access on
 dissolve_free_huge_pages()
To: Michal Hocko <mhocko@kernel.org>
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Cc: Rui Teng <rui.teng@linux.vnet.ibm.com>, linux-mm@kvack.org,
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From: Dave Hansen <dave.hansen@linux.intel.com>
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Date: Wed, 21 Sep 2016 09:32:10 -0700
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On 09/21/2016 09:27 AM, Michal Hocko wrote:
> That was not my point. I wasn't very clear probably. Offlining can fail
> which shouldn't be really surprising. There might be a kernel allocation
> in the particular block which cannot be migrated so failures are to be
> expected. I just do not see how offlining in the middle of a gigantic
> page is any different from having any other unmovable allocation in a
> block. That being said, why don't we simply refuse to offline a block
> which is in the middle of a gigantic page.

Don't we want to minimize the things that can cause an offline to fail?
 The code to fix it here doesn't seem too bad.