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Subject: Re: [PATCH v3 5/6] mm/gup: migrate pinned pages out of movable zone
To:     Jason Gunthorpe <jgg@ziepe.ca>
Cc:     Pavel Tatashin <pasha.tatashin@soleen.com>,
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From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <69beec6b-8518-aa47-5a08-fd5f85cf9430@redhat.com>
Date:   Mon, 14 Dec 2020 15:21:21 +0100
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On 14.12.20 14:36, Jason Gunthorpe wrote:
> On Sat, Dec 12, 2020 at 08:29:11AM +0100, David Hildenbrand wrote:
> 
>>> Racing with another GUP in another thread is also not reasonable, so
>>> failing to isolate can't be a failure
>>
>> Having VMs with multiple vfio containers is certainly realistic, and
>> optimizing in user space to do vfio mappings concurrently doesn‘t
>> sound too crazy to me. But I haven‘t checked if vfio common code
>> already handles such concurrency.
> 
> There is a lot more out there than vfio.. RDMA already does concurrent
> pin_user_pages in real apps

I actually misread your comment. I think we both agree that temporary
isolation failures must not lead to a failure.

-- 
Thanks,

David / dhildenb