[Qemu-devel] [RFC v2 0/6] dataplane: switch to N:M devices-per-thread model

[Stefan Hajnoczi <stefanha@redhat.com>]

This series moves the event loop thread out of dataplane code.  It makes
-object iothread,id=foo a separate concept.  This makes it possible to bind
several devices to the same iothread.

Syntax:

  qemu -object iothread,id=iothread0 \
       -device virtio-blk-pci,iothread=iothread0,x-data-plane=on,...

For backwards-compatibility the iothread= parameter can be omitted.  A
per-device IOThread will be created behind the scenes (just like the old 1:1
threading model).

This series includes the aio_context_acquire/release API which makes it easy to
synchronize access to AioContext across threads.

Mike: My goal is to get this into QEMU 2.0.  How can we get the QContext ball
rolling?  The only feature I'm missing is an API to query thread IDs for
iothread host CPU affinity.  Besides that the IOThread object does what I need
for virtio-blk dataplane.

v2:
 * Based off Igor's "-object/object-add support custom location and 2nd stage
   initialization" series
 * Dropped dedicated -iothread option in favor of -object
 * Avoid re-acquiring rfifo in iothread_run() [mdroth]

Stefan Hajnoczi (6):
  rfifolock: add recursive FIFO lock
  aio: add aio_context_acquire() and aio_context_release()
  iothread: add I/O thread object
  qdev: add get_pointer_and_free() for temporary strings
  iothread: add "iothread" qdev property type
  dataplane: replace internal thread with IOThread

 Makefile.objs                    |   1 +
 async.c                          |  18 ++++++
 hw/block/dataplane/virtio-blk.c  |  95 +++++++++++++++-------------
 hw/core/qdev-properties-system.c |  65 +++++++++++++++++++
 include/block/aio.h              |  18 ++++++
 include/hw/qdev-properties.h     |   3 +
 include/hw/virtio/virtio-blk.h   |   8 ++-
 include/qemu/rfifolock.h         |  54 ++++++++++++++++
 include/sysemu/iothread.h        |  30 +++++++++
 iothread.c                       | 132 +++++++++++++++++++++++++++++++++++++++
 tests/Makefile                   |   2 +
 tests/test-aio.c                 |  58 +++++++++++++++++
 tests/test-rfifolock.c           |  90 ++++++++++++++++++++++++++
 util/Makefile.objs               |   1 +
 util/rfifolock.c                 |  78 +++++++++++++++++++++++
 15 files changed, 609 insertions(+), 44 deletions(-)
 create mode 100644 include/qemu/rfifolock.h
 create mode 100644 include/sysemu/iothread.h
 create mode 100644 iothread.c
 create mode 100644 tests/test-rfifolock.c
 create mode 100644 util/rfifolock.c

-- 
1.8.4.2