mlx5: Preallocate ktls tags asynchronouslyHEADmain

Change tag preallocation to happen asynchronously when an interface is
brought up, so as to reduce boot times when preallocating tags.

- A new mlx5-tls-prealloc_wq is allocated when preallocation is
  desired, and started when an interface is opened

- The bulk of the prealloc code remains the same, except the
  allocations are now M_NOWAIT. M_NOWAIT is needed because, since the
  preallocation is done asynchronously, and since tag allocation is
  not instant, we could race with a real TLS session trying to
  allocate a tag. Note that in this case, we take allocation failure
  as a sign that we were unable to obtain the entire zone due to there
  being other consumers.  This was suggested by @markj as a way to
  keep things simple, after discussing why uma_zone_get_cur() didn't
  immediately report a fully allocated zone.  If this turns out to be
  problematic, we could use uma_zone_set_maxaction() to stop
  pre-allocations (also suggested by Mark)

Reviewed by: glebius, kib, markj
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D53570

0 files changed, 0 insertions, 0 deletions