Re: [dpdk-dev] [PATCH v2 4/5] mem: use memfd for no-huge mode

[Tiwei Bie <tiwei.bie@intel.com>]

On Tue, Dec 11, 2018 at 04:43:31PM +0000, Anatoly Burakov wrote:
> When running in no-huge mode, we anonymously allocate our memory.
> While this works for regular NICs and vdev's, it's not suitable
> for memory sharing scenarios such as virtio with vhost_user
> backend.
> 
> To fix this, allocate no-huge memory using memfd, and register
> it with memalloc just like any other memseg fd. This will enable
> using rte_memseg_get_fd() API with --no-huge EAL flag.
> 
> Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
> ---
> 
> Notes:
>     v2:
>     - Detect memfd support at compile time
>     - Change memfd-related log level to debug
> 
>  doc/guides/rel_notes/release_19_02.rst   |  5 +++
>  lib/librte_eal/linuxapp/eal/eal_memory.c | 54 +++++++++++++++++++++++-
>  2 files changed, 57 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/guides/rel_notes/release_19_02.rst b/doc/guides/rel_notes/release_19_02.rst
> index 960098582..420d51b5b 100644
> --- a/doc/guides/rel_notes/release_19_02.rst
> +++ b/doc/guides/rel_notes/release_19_02.rst
> @@ -23,6 +23,11 @@ DPDK Release 19.02
>  New Features
>  ------------
>  
> +* **Support for using VirtIO without hugepages**
> +
> +  The --no-huge mode was augmented to use memfd-backed memory (on systems that
> +  support memfd), to allow using VirtIO-based NICs without hugepages.

It would be better to say virtio-user here, because virtio NICs
e.g. the one emulated by QEMU, could be something quite different.

> +
>  .. This section should contain new features added in this release.
>     Sample format:
>  
[...]