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Subject: Re: Pinning ZONE_MOVABLE pages
To:     Michal Hocko <mhocko@suse.com>,
        Pavel Tatashin <pasha.tatashin@soleen.com>
Cc:     Vlastimil Babka <vbabka@suse.cz>, linux-mm <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Oscar Salvador <osalvador@suse.de>,
        Dan Williams <dan.j.williams@intel.com>,
        Sasha Levin <sashal@kernel.org>,
        Tyler Hicks <tyhicks@linux.microsoft.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, sthemmin@microsoft.com,
        John Hubbard <jhubbard@nvidia.com>
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From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <43922bf4-c818-e675-2369-10097c460ac4@redhat.com>
Date:   Tue, 24 Nov 2020 09:44:33 +0100
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On 24.11.20 09:43, Michal Hocko wrote:
> On Mon 23-11-20 11:31:59, Pavel Tatashin wrote:
> [...]
>> Also, we still need to take care of the fault scenario.
> 
> Forgot to reply to this part. I believe you mean this to be fault at gup
> time, right? Then the easiest way forward would be to either add yet
> another scoped flag or (maybe) better to generalize memalloc_nocma_* to
> imply that the allocated memory is going to be unmovable so drop
> __GFP_MOVABLE and also forbid CMA. I have to admit that I do not
> remember why long term pin on CMA pages is ok to go to movable but I
> strongly suspect this is just shifting problem around.

Agreed.


-- 
Thanks,

David / dhildenb