Re: [PATCH for-next v2 0/5] Introduce Completion Counters

[Doug Ledford <doug.ledford@hpe.com>]

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On 4/16/26 4:23 PM, Michael Margolin wrote:
> Add core infrastructure for Completion Counters, a light-weight
> alternative to polling CQ for tracking operation completions. The
> related rdma-core interface proposal is linked in [1].
> 
> Define the UVERBS_OBJECT_COMP_CNTR ioctl object with create, destroy,
> set, inc and read methods for both success and error counters. Add a
> QP attach method on the QP object to associate a completion counter
> with a queue pair.
> 
> Completion Counters can be backed by user-provided VA or dmabuf or by
> internal device/driver memory. Common command infrastructure allows any
> of the implementations to support the various device capabilities.
> 
> Add EFA Completion Counters support as first implementer.
> 
> [1] https://github.com/linux-rdma/rdma-core/pull/1701
> 
> ---
> Changes in v2:
> - United set, inc and read flows for successful and error completions
>    counters
> - Added comp_cntr usage count
> - Minor cleanups
> - Link to v1: https://lore.kernel.org/all/20260407115424.13359-1-mrgolin@amazon.com/
> 
> Michael Margolin (5):
>    RDMA/core: Add Completion Counters support
>    RDMA/core: Prevent destroying in-use completion counters
>    RDMA/core: Add Completion Counters to resource tracking
>    RDMA/efa: Update device interface
>    RDMA/efa: Add Completion Counters support
> 
>   drivers/infiniband/core/Makefile              |   1 +
>   drivers/infiniband/core/device.c              |   7 +
>   drivers/infiniband/core/nldev.c               |   1 +
>   drivers/infiniband/core/rdma_core.h           |   1 +
>   drivers/infiniband/core/restrack.c            |   2 +
>   drivers/infiniband/core/uverbs_cmd.c          |   1 +
>   .../core/uverbs_std_types_comp_cntr.c         | 299 ++++++++++++++++++
>   drivers/infiniband/core/uverbs_std_types_qp.c |  65 +++-
>   drivers/infiniband/core/uverbs_uapi.c         |   1 +
>   drivers/infiniband/core/verbs.c               |   1 +
>   drivers/infiniband/hw/efa/efa.h               |  13 +
>   .../infiniband/hw/efa/efa_admin_cmds_defs.h   | 185 ++++++++++-
>   drivers/infiniband/hw/efa/efa_com_cmd.c       | 106 +++++++
>   drivers/infiniband/hw/efa/efa_com_cmd.h       |  36 +++
>   drivers/infiniband/hw/efa/efa_io_defs.h       |  62 +++-
>   drivers/infiniband/hw/efa/efa_main.c          |   6 +
>   drivers/infiniband/hw/efa/efa_verbs.c         | 171 ++++++++++
>   include/rdma/ib_verbs.h                       |  41 +++
>   include/rdma/restrack.h                       |   4 +
>   include/uapi/rdma/efa-abi.h                   |   1 +
>   include/uapi/rdma/ib_user_ioctl_cmds.h        |  50 +++
>   include/uapi/rdma/ib_user_ioctl_verbs.h       |  14 +
>   include/uapi/rdma/ib_user_verbs.h             |   2 +-
>   23 files changed, 1063 insertions(+), 7 deletions(-)
>   create mode 100644 drivers/infiniband/core/uverbs_std_types_comp_cntr.c
> 

Apologies, my last email I selected the wrong cover letter.  I knew that 
v2 was out and I had intended to comment on it (and I had already 
checked and didn't see this in the 7.1 window merge request).

So, just to make sure my comment is in the right thread for tracking 
tools to process, we have hardware counters and if this isn't already 
merged, then I'll prioritize making sure this API will work reasonably 
for our hardware too.

-- 
Doug Ledford <doug.ledford@hpe.com>
     GPG KeyID: B826A3330E572FDD
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