[net-next v5 0/2] mlx5: Add netdev-genl queue stats

[Joe Damato]

Greetings:

Welcome to v5.

Switched from RFC to just a v5, because I think this is pretty close.
Minor changes from v4 summarized below in the changelog.

Note that my NIC does not seem to support PTP and I couldn't get the
mlnx-tools mlnx_qos script to work, so I was only able to test the
following cases:

- device up at boot
- adjusting queue counts
- device down (e.g. ip link set dev eth4 down)

Please see the commit message of patch 2/2 for more details on output
and test cases.

rfcv4 thread:
  https://lore.kernel.org/linux-kernel/20240604004629.299699-1-jdamato@xxxxxxxxxx/T/

Thanks,
Joe

rfcv4 -> v5:
 - Patch 1/2: change variable name 'mlx5e_qid' to 'txq_ix'.
 - Patch 2/2:
    - remove logic in mlx5e_get_queue_stats_rx for PTP. PTP RX are
      always reported in base.
    - report PTP TX in mlx5e_get_base_stats only if:
      - PTP has ever been opened, and
      - either PTP is NULL (closed) or the MLX5E_PTP_STATE_TX bit in its
        state is not set

    Otherwise, PTP TX will be reported when the txq_ix is passed into
    mlx5e_get_queue_stats_tx

rfcv3 -> rfcv4:
 - Patch 1/2 now creates a mapping (priv->txq2sq_stats) which maps txq
   indices to sq_stats structures so stats can be accessed directly.
   This mapping is kept up to date along side txq2sq.

 - Patch 2/2:
   - All mutex_lock/unlock on state_lock has been dropped.
   - mlx5e_get_queue_stats_rx now uses ASSERT_RTNL() and has a special
     case for PTP. If PTP was ever opened, is currently opened, and the
     channel index matches, stats for PTP RX are output.
   - mlx5e_get_queue_stats_tx rewritten to use priv->txq2sq_stats. No
     corner cases are needed here because any txq idx (passed in as i)
     will have an up to date mapping in priv->txq2sq_stats.
   - mlx5e_get_base_stats:
     - in the RX case:
       - iterates from [params.num_channels, stats_nch) collecting
         stats.
       - if ptp was ever opened but is currently closed, add the PTP
         stats.
     - in the TX case:
       - handle 2 cases:
         - the channel is available, so sum only the unavailable TCs
           [mlx5e_get_dcb_num_tc, max_opened_tc).
         - the channel is unavailable, so sum all TCs [0, max_opened_tc).
       - if ptp was ever opened but is currently closed, add the PTP
         sq stats.

v2 -> rfcv3:
 - Added patch 1/2 which creates some helpers for computing the txq_ix
   and ch_ix/tc_ix.

 - Patch 2/2 modified in several ways:
   - Fixed variable declarations in mlx5e_get_queue_stats_rx to be at
     the start of the function.
   - mlx5e_get_queue_stats_tx rewritten to access sq stats directly by
     using the helpers added in the previous patch.
   - mlx5e_get_base_stats modified in several ways:
     - Took the state_lock when accessing priv->channels.
     - For the base RX stats, code was simplified to call
       mlx5e_get_queue_stats_rx instead of repeating the same code.
     - For the base TX stats, I attempted to implement what I think
       Tariq suggested in the previous thread:
         - for available channels, only unavailable TC stats are summed
	 - for unavailable channels, all stats for TCs up to
	   max_opened_tc are summed.

v1 - > v2:
  - Essentially a full rewrite after comments from Jakub, Tariq, and
    Zhu.

Joe Damato (2):
  net/mlx5e: Add txq to sq stats mapping
  net/mlx5e: Add per queue netdev-genl stats

 drivers/net/ethernet/mellanox/mlx5/core/en.h  |   2 +
 .../net/ethernet/mellanox/mlx5/core/en/qos.c  |  13 +-
 .../net/ethernet/mellanox/mlx5/core/en_main.c | 143 +++++++++++++++++-
 3 files changed, 155 insertions(+), 3 deletions(-)

-- 
2.25.1