[UNIKRAFT PATCH,v2,00/15] Introduce Ring Buffer Implementation

[Alexander Jung <a.jung@xxxxxxxxxxx>]

This series introduces a port of FreeBSD's buf_ring.{h,c} implementation for use
within Unikraft.  This simple ring buffer can be used for message passing in
queues, for example within a AF_UNIX socket implementation between two 
threads.  The implementation is therefore thread safe and provides a generic 
data field which is initialized to the desired ring buffer length.

The implementation is provided within ukmpi as a new option, LIBUKMPI_RING, 
which exposes the following new methods:

 - uk_ring_alloc
 - uk_ring_free
 - uk_ring_enqueue
 - uk_ring_dequeue
 - uk_ring_dequeue_single
 - uk_ring_advance_single
 - uk_ring_putback_single
 - uk_ring_peek
 - uk_ring_peek_clear_single
 - uk_ring_full
 - uk_ring_empty
 - uk_ring_count

The port is currently limited, with no support for reading atomic values from
ARM{32,64} CPU registers (described in the comments inline).  As a result, use 
of the ring buffer implementation is untested on ARM.

Alexander Jung (15):
  lib/ukring: Import simple ring buffer from FreeBSD
  lib/ukring: {ring.c, ring.h} Fix checkpatch errors and spacing.
  lib/ukring: Adapt {ring.c, ring.h} to Unikraft
  lib/ukring: Re-prefix methods and structs from buf_ to uk_
  lib/ukring: Remove br_ prefix and rename br variable
  lib/ukring: Disable use of cpu_spinwait function
  lib/ukring: Rename single and multiple consumer functions.
  lib/ukring: Use Unikraft to enable ring buffer debugging
  lib/ukring: Remove unsupported cache line size
  lib/ukring: Disable use of CPU prefetching
  lib/ukring: Properly commment {ring.c, ring.h}
  lib/ukring: Provide KConfig menu option for microlibrary
  lib/ukring: Target files to build for the microlibrary
  lib/ukring: Register ukring with Unikraft
  lib/ukring: Fix unitialized variable

 lib/Makefile.uk              |   1 +
 lib/ukring/Config.uk         |   7 +
 lib/ukring/Makefile.uk       |   6 +
 lib/ukring/exportsyms.uk     |  12 +
 lib/ukring/include/uk/ring.h | 482 +++++++++++++++++++++++++++++++++++
 lib/ukring/ring.c            |  86 +++++++
 6 files changed, 594 insertions(+)
 create mode 100644 lib/ukring/Config.uk
 create mode 100644 lib/ukring/Makefile.uk
 create mode 100644 lib/ukring/exportsyms.uk
 create mode 100644 lib/ukring/include/uk/ring.h
 create mode 100644 lib/ukring/ring.c

-- 
2.20.1