[Qemu-devel] [PATCH v4 0/6] dataplane: switch to N:M devices-per-thread model

[Stefan Hajnoczi <stefanha@redhat.com>]

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]

v3:
 * Fixed "Reliquinish" typo [fam]
 * Rebased onto qemu.git/master which now has Igor's -object improvements

v4:
 * Rename qdev property to virtio-blk-pci,x-iothread= since we will switch to
   QOM links once object_property_add_link() is fixed [bonzini]

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

Syntax:

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

After this series I will send separate patches for a "query-iothreads" command
that returns thread IDs similar to "query-cpus".  This will allow binding
dataplane threads to host CPUs.

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  |  96 +++++++++++++++++-------------
 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                       | 123 +++++++++++++++++++++++++++++++++++++++
 tests/Makefile                   |   2 +
 tests/test-aio.c                 |  58 ++++++++++++++++++
 tests/test-rfifolock.c           |  90 ++++++++++++++++++++++++++++
 util/Makefile.objs               |   1 +
 util/rfifolock.c                 |  78 +++++++++++++++++++++++++
 15 files changed, 601 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

-- 
1.8.5.3