[dpdk-dev] [PATCH v3 5/6] net/mlx4: add control of excessive memory pinning by kernel

[Stephen Hemminger]

On Mon,  1 Apr 2019 14:17:56 -0700
Yongseok Koh <yskoh at mellanox.com> wrote:

> +- ``mr_ext_memseg_en`` parameter [int]
> +
> +  A nonzero value enables extending memseg when registering DMA memory. If
> +  enabled, the number of entries in MR (Memory Region) lookup table on datapath
> +  is minimized and it benefits performance. On the other hand, it worsens memory
> +  utilization because registered memory is pinned by kernel driver. Even if a
> +  page in the extended chunk is freed, that doesn't become reusable until the
> +  entire memory is freed.
> +
> +  Enabled by default.
> +

This module parameter does not appear in the upstream Linux kernel drivers (even 5.2).
What code are you referring to?