netdev - Re: [PATCH v11 00/25] mm/gup: track dma-pinned pages: FOLL

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAPcyv4hMvTmb5X8gNtXnapJFR1qej1bKto2fvv9zUtebHMhvVw@mail.gmail.com>
Date:   Fri, 20 Dec 2019 16:51:12 -0800
From:   Dan Williams <dan.j.williams@...el.com>
To:     John Hubbard <jhubbard@...dia.com>
Cc:     Jan Kara <jack@...e.cz>, Leon Romanovsky <leon@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Alex Williamson <alex.williamson@...hat.com>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Björn Töpel <bjorn.topel@...el.com>,
        Christoph Hellwig <hch@...radead.org>,
        Daniel Vetter <daniel@...ll.ch>,
        Dave Chinner <david@...morbit.com>,
        David Airlie <airlied@...ux.ie>,
        "David S . Miller" <davem@...emloft.net>,
        Ira Weiny <ira.weiny@...el.com>,
        Jason Gunthorpe <jgg@...pe.ca>, Jens Axboe <axboe@...nel.dk>,
        Jonathan Corbet <corbet@....net>,
        Jérôme Glisse <jglisse@...hat.com>,
        Magnus Karlsson <magnus.karlsson@...el.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Michal Hocko <mhocko@...e.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Paul Mackerras <paulus@...ba.org>,
        Shuah Khan <shuah@...nel.org>,
        Vlastimil Babka <vbabka@...e.cz>, bpf@...r.kernel.org,
        Maling list - DRI developers 
        <dri-devel@...ts.freedesktop.org>, KVM list <kvm@...r.kernel.org>,
        linux-block@...r.kernel.org,
        Linux Doc Mailing List <linux-doc@...r.kernel.org>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        linux-kselftest@...r.kernel.org,
        "Linux-media@...r.kernel.org" <linux-media@...r.kernel.org>,
        linux-rdma <linux-rdma@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        Netdev <netdev@...r.kernel.org>, Linux MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Maor Gottlieb <maorg@...lanox.com>
Subject: Re: [PATCH v11 00/25] mm/gup: track dma-pinned pages: FOLL_PIN

On Fri, Dec 20, 2019 at 4:41 PM John Hubbard <jhubbard@...dia.com> wrote:
>
> On 12/20/19 4:33 PM, Dan Williams wrote:
> ...
> >> I believe there might be also a different solution for this: For
> >> transparent huge pages, we could find a space in 'struct page' of the
> >> second page in the huge page for proper pin counter and just account pins
> >> there so we'd have full width of 32-bits for it.
> >
> > That would require THP accounting for dax pages. It is something that
> > was probably going to be needed, but this would seem to force the
> > issue.
> >
>
> Thanks for mentioning that, it wasn't obvious to me yet.
>
> How easy is it for mere mortals outside of Intel, to set up a DAX (nvdimm?)
> test setup? I'd hate to go into this without having that coverage up
> and running. It's been sketchy enough as it is. :)

You too can have the power of the gods for the low low price of a
kernel command line parameter, or a qemu setup.

Details here:

https://nvdimm.wiki.kernel.org/how_to_choose_the_correct_memmap_kernel_parameter_for_pmem_on_your_system
https://nvdimm.wiki.kernel.org/pmem_in_qemu