Date: Thu, 27 Jul 2017 08:56:52 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Jerome Glisse <jglisse@redhat.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com,
        Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com,
        Joonsoo Kim <js1304@gmail.com>, Andi Kleen <ak@linux.intel.com>,
        Daniel Kiper <daniel.kiper@oracle.com>,
        Igor Mammedov <imammedo@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        Thomas Gleixner <tglx@linutronix.de>, Tony Luck <tony.luck@intel.com>,
        Will Deacon <will.deacon@arm.com>
Subject: Re: [RFC PATCH 0/5] mm, memory_hotplug: allocate memmap from
 hotadded memory
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References: <20170726083333.17754-1-mhocko@kernel.org>
 <20170726210657.GE21717@redhat.com>
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On Wed 26-07-17 17:06:59, Jerome Glisse wrote:
[...]
> This does not seems to be an opt-in change ie if i am reading patch 3
> correctly if an altmap is not provided to __add_pages() you fallback
> to allocating from begining of zone. This will not work with HMM ie
> device private memory. So at very least i would like to see some way
> to opt-out of this. Maybe a new argument like bool forbid_altmap ?

OK, I see! I will think about how to make a sane api for that.

Thanks!
-- 
Michal Hocko
SUSE Labs