From b60d006cd14743907d75a6944ed24a692e4f79ae Mon Sep 17 00:00:00 2001 From: Alexander Kozyrev Date: Thu, 10 Mar 2022 07:06:36 +0200 Subject: [PATCH] doc: mention mlx5 MPRQ incompatibility with external buffers Multi-Packet Rx queue uses PMD-managed buffers to store packets. These buffers are externally attached to user mbufs. This conflicts with the feature that allows using user-managed externally attached buffers in an application. Add the corresponding limitation to MLX5 documentation that MPRQ and external data buffers cannot be used together. Signed-off-by: Alexander Kozyrev --- doc/guides/nics/mlx5.rst | 3 +++ 1 file changed, 3 insertions(+) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 3c3687ac73..4805d08a76 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -261,6 +261,9 @@ Limitations Rx mbufs must be freed before the device is closed. Otherwise, the mempool of the external buffers will be freed by PMD and the application which still holds the external buffers may be corrupted. + User-managed mempools with external pinned data buffers + cannot be used in conjunction with MPRQ + since packets may be already attached to PMD-managed external buffers. - If Multi-Packet Rx queue is configured (``mprq_en``) and Rx CQE compression is enabled (``rxq_cqe_comp_en``) at the same time, RSS hash result is not fully -- 2.20.1