Commit Graph

3 Commits

Author SHA1 Message Date
Pedro F. Giffuni
fe267a5590 sys: general adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:23:17 +00:00
Robert Watson
f2d2d69438 Rework netisr policy mechanism so that per-protocol dispatch policies can
be represented:

- A single policy namespace is defined, consisting of four possible
  policies: "default" to use the global default, "deferred" to force
  deferred dispatch, "direct" to employ direct dispatch where possible, and
  "hybrid" which makes a dynamic decision based on CPU affinity, ordering,
  etc.  Routines are implemented to convert between strings and an integer
  namespace.

- A new global variable, netisr_dispatch_policy, subsumes existing global
  variables for direct dispatch, forced direct dispatch, etc, and is used
  for explicit policy interpretation and composition.  Old variables remain
  so that they can be exported by legacy sysctls for use by old netstat(1)
  binaries.  A new sysctl and tunable, netisr.dispatch.policy, accepts the
  above strings for specifying a global policy default.

- The protocol registration structure, netisr_handler, grows an nh_dispatch
  field, which accepts a per-policy policy override.  The default value is
  '0', which corresponds to "default", meaning that protocols will accept
  the global default policy unless otherwise specified.

- Policies are now interpreted and composed explicitly at various points in
  packet dispatch; protocol policies override global policies.

- Protocols grow the ability to express a non-opinion about affinity even
  when implenting m2cpuid by returning NETISR_CPUID_NONE.  In that case, the
  framework falls back on source ordering, rather than simply using the
  current CPU.

These changes are in support of allowing link layer re-dispatch based on
RSS or similar hashes provided by NICs, especially in the case where the
number of hardware receive queues matches hardware core count, rather than
hardware thread count, requiring further software redistributeon.  (i.e.,
on RMI XLR).

MFC after:      3 weeks
Reviewed by:    bz
Sponsored by:   Juniper Networks, Inc.
2011-05-24 12:34:19 +00:00
Robert Watson
938448cd87 Changes to support crashdump analysis of netisr:
- Rename the netisr protocol registration array, 'np' to 'netisr_proto',
  in order to reduce the chances of symbol name collisions.  It remains
  statically defined, but it will be looked up by netstat(1).

- Move certain internal structure definitions from netisr.c to
  netisr_internal.h so that netstat(1) can find them.  They remain
  private, and should not be used for any other purpose (for example,
  they should not be used by kernel modules, which must instead use the
  public interfaces in netisr.h).

- Store a kernel-compiled version of NETISR_MAXPROT in the global variable
  netisr_maxprot, and export via a sysctl, so that it is available for use
  by netstat(1).  This is especially important for crashdump
  interpretation, where the size of the workstream structure is determined
  by the maximum number of protocols compiled into the kernel.

MFC after:	1 week
Sponsored by:	Juniper Networks
2010-03-01 00:42:36 +00:00