Date:   Tue, 23 Nov 2021 10:07:09 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     David Hildenbrand <david@redhat.com>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Andrew Dona-Couch <andrew@donacou.ch>,
        Andrew Morton <akpm@linux-foundation.org>,
        Drew DeVault <sir@cmpwn.com>,
        Ammar Faizi <ammarfaizi2@gnuweeb.org>,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        io_uring Mailing List <io-uring@vger.kernel.org>,
        Pavel Begunkov <asml.silence@gmail.com>, linux-mm@kvack.org
Subject: Re: [PATCH] Increase default MLOCK_LIMIT to 8 MiB
Message-ID: <20211123140709.GB5112@ziepe.ca>
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On Tue, Nov 23, 2021 at 02:39:19PM +0100, David Hildenbrand wrote:
> > 
> >> 2) Could be provide a mmu variant to ordinary users that's just good
> >> enough but maybe not as fast as what we have today? And limit
> >> FOLL_LONGTERM to special, privileged users?
> > 
> > rdma has never been privileged
> 
> Feel free to correct me if I'm wrong: it requires special networking
> hardware and the admin/kernel has to prepare the system in a way such
> that it can be used.

Not really, plug in the right PCI card and it works

"special" is a bit of a reach since almost every NIC sold in the > 100GB
segment supports some RDMA.

Jason