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Date:   Tue, 11 Jun 2019 06:52:12 -0700
From:   Christoph Hellwig <hch@infradead.org>
To:     Pingfan Liu <kernelfans@gmail.com>
Cc:     John Hubbard <jhubbard@nvidia.com>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        Ira Weiny <ira.weiny@intel.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        Keith Busch <keith.busch@intel.com>,
        Christoph Hellwig <hch@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHv3 1/2] mm/gup: fix omission of check on FOLL_LONGTERM in
 get_user_pages_fast()
Message-ID: <20190611135212.GA4591@infradead.org>
References: <1559725820-26138-1-git-send-email-kernelfans@gmail.com>
 <20190605144912.f0059d4bd13c563ddb37877e@linux-foundation.org>
 <CAFgQCTur5ReVHm6NHdbD3wWM5WOiAzhfEXdLnBGRdZtf7q1HFw@mail.gmail.com>
 <2b0a65ec-4fb0-430e-3e6a-b713fb5bb28f@nvidia.com>
 <CAFgQCTtS7qOByXBnGzCW-Rm9fiNsVmhQTgqmNU920m77XyAwZQ@mail.gmail.com>
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On Tue, Jun 11, 2019 at 08:29:35PM +0800, Pingfan Liu wrote:
> Unable to get a NVME device to have a test. And when testing fio on the

How would a nvme test help?  FOLL_LONGTERM isn't used by any performance
critical path to start with, so I don't see how this patch could be
a problem.