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Date:   Tue, 7 Jan 2020 14:36:23 +0100
From:   Michal Hocko <mhocko@kernel.org>
To:     lantianyu1986@gmail.com
Cc:     kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com,
        sashal@kernel.org, akpm@linux-foundation.org,
        michael.h.kelley@microsoft.com, david@redhat.com,
        Tianyu Lan <Tianyu.Lan@microsoft.com>,
        linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, vkuznets@redhat.com, eric.devolder@oracle.com,
        vbabka@suse.cz, osalvador@suse.de, pavel.tatashin@microsoft.com,
        rppt@linux.ibm.com
Subject: Re: [RFC PATCH V2 2/10] mm: expose is_mem_section_removable() symbol
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 <20200107130950.2983-3-Tianyu.Lan@microsoft.com>
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On Tue 07-01-20 21:09:42, lantianyu1986@gmail.com wrote:
> From: Tianyu Lan <Tianyu.Lan@microsoft.com>
> 
> Hyper-V balloon driver will use is_mem_section_removable() to
> check whether memory block is removable or not when receive
> memory hot remove msg. Expose it.

I do not think this is a good idea. The check is inherently racy. Why
cannot the balloon driver simply hotremove the region when asked?
-- 
Michal Hocko
SUSE Labs