Question: PMD behaviour without hugepages in DPDK 23.07 (XDP PMD in Kubernetes)

Question: PMD behaviour without hugepages in DPDK 23.07 (XDP PMD in Kubernetes)

[Wan Bingbing]

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Dear DPDK team,

We are currently deploying an application utilizing Seastar and DPDK
(version 23.07) with the XDP PMD inside a Kubernetes environment. Due to
infrastructure restrictions, we cannot allocate hugepages on the Kubernetes
nodes.

In this environment, DPDK fails to initialize the XDP PMD because
hugepage-backed memory cannot be created. Although the EAL is not started
with the --no-huge parameter, no hugepages are available to DPDK,
preventing the PMD from sending or receiving packets.

We are aware of the known issue documented in the DPDK release notes ("PMD
does not work with --no-huge EAL command line parameter"), which explains
that PMDs rely on hugepage-backed memory because DPDK does not store the
necessary physical/IOVA information for memory allocated via malloc/mmap.

Given this dependency, we have the following questions:

1. Is there a currently supported method to run a hardware PMD
(specifically the XDP PMD) without hugepages, or is hugepage-backed memory
strictly required for all hardware PMDs?
2. Are there any ongoing efforts or future plans to support PMD operation
in a non-hugepage mode?
3. If this limitation is architectural and not planned to be addressed,
could you please confirm this? This confirmation would allow us to evaluate
alternative approaches, such as using AF_XDP without DPDK or relying on the
Seastar native stack.

Any guidance or recommendations from the maintainers on how to proceed
would be greatly appreciated.

Thank you for your time.

Best regards,
Wan Bingbing

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Re: Question: PMD behaviour without hugepages in DPDK 23.07 (XDP PMD in Kubernetes)

[Bruce Richardson]

On Fri, Nov 21, 2025 at 10:15:39PM +0800, Wan Bingbing wrote:
>    Dear DPDK team,
>    We are currently deploying an application utilizing Seastar and DPDK
>    (version 23.07) with the XDP PMD inside a Kubernetes environment. Due
>    to infrastructure restrictions, we cannot allocate hugepages on the
>    Kubernetes nodes.
>    In this environment, DPDK fails to initialize the XDP PMD because
>    hugepage-backed memory cannot be created. Although the EAL is not
>    started with the --no-huge parameter, no hugepages are available to
>    DPDK, preventing the PMD from sending or receiving packets.
>    We are aware of the known issue documented in the DPDK release notes
>    ("PMD does not work with --no-huge EAL command line parameter"), which
>    explains that PMDs rely on hugepage-backed memory because DPDK does not
>    store the necessary physical/IOVA information for memory allocated via
>    malloc/mmap.
>    Given this dependency, we have the following questions:
>    1. Is there a currently supported method to run a hardware PMD
>    (specifically the XDP PMD) without hugepages, or is hugepage-backed
>    memory strictly required for all hardware PMDs?
>    2. Are there any ongoing efforts or future plans to support PMD
>    operation in a non-hugepage mode?
>    3. If this limitation is architectural and not planned to be addressed,
>    could you please confirm this? This confirmation would allow us to
>    evaluate alternative approaches, such as using AF_XDP without DPDK or
>    relying on the Seastar native stack.
>    Any guidance or recommendations from the maintainers on how to proceed
>    would be greatly appreciated.
>    Thank you for your time.
>    Best regards,
>    Wan Bingbing

For non-HW PMDs like the AF_XDP driver*, AFAIK it should be feasible to
have it work in no-huge mode. However, as far as I am aware, there is
nobody currently looking into this.

Regards,
/Bruce

* yes, it does use HW, but really the kernel driver does most of the work,
  so in practice its more like a SW or virtual driver.