Weird NFS client lock up with Mellanox cards :/

[Justin Clift]

Hi all,

Brian Krusic (CC'd), has been kind enough to put time into some
performance testing of Mellanox ConnectX-3 Pro cards in 40GbE mode,
with FreeNAS 9.10-STABLE.  (That uses FreeBSD 10-STABLE as it's
base OS)

Weirdly, his NFS clients are locking up when using Mellanox cards,
but not with SolarFlare ones.

  https://bugs.freenas.org/issues/7659#note-40

Comparing the OFED code in FreeNAS 9.10-STABLE to FreeNSD 10-STABLE,
there's one patch difference.  It's a recent one from 3 days ago:

  MFC r301877
  Add a missing error check for a malloc() call in idr_get().
  https://github.com/freebsd/freebsd/commit/03f3328da077d2def40be7dea8d13c74c2ccd447

Does anyone know if this missing patch could result in a slow down
of NFS clients (but not Samba/SMB)?  Maybe memory leak style, leading
to a lack of resources or something?

Hoping it's really this simple.  But if not... does anyone have
suggestions on what to try for figuring this out?

Regards and best wishes,

Justin Clift

--
"My grandfather once told me that there are two kinds of people: those
who work and those who take the credit. He told me to try to be in the
first group; there was less competition there."
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