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[Qemu-devel] [RFC 00/13] dataplane: use block layer
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [RFC 00/13] dataplane: use block layer |
Date: |
Fri, 14 Jun 2013 11:48:20 +0200 |
This series adds image format, QMP 'transation', and QMP 'block_resize' support
to dataplane. This is done by replacing custom Linux AIO code with QEMU block
layer APIs.
In order for block layer APIs to be safe, bdrv_drain_all() is modified to be
aware of device emulation threads (like dataplane).
BlockDevOps->drain_threads_cb() is introduced as a way to stop device emulation
threads temporarily. Device emulation threads may resume after this main loop
iteration completes, which is enough to allow code running under the QEMU
global mutex a chance to use the block device temporarily.
bdrv_get_aio_context() is dropped in favor of a thread-local AioContext
pointer. This allows qemu_bh_new(), qemu_aio_wait(), and friends to
automatically use the right AioContext. When we introduce a BlockDriverState
lock in the future, it will be possible to use block devices from multiple
threads arbitrarily (right now we only allow it if bdrv_drain_all() is used).
Three open issues:
* Timers only work in the main loop, so I/O throttling is ignored and QED is
unsafe with x-data-plane=on.
* Need to test with NBD, Gluster, and other non-file protocols.
* Need to compare performance against custom Linux AIO code.
Paolo Bonzini (2):
exec: do not use qemu/tls.h
qemu-thread: add TLS wrappers
Stefan Hajnoczi (11):
block: fix bdrv_flush() ordering in bdrv_close()
dataplane: sync virtio.c and vring.c virtqueue state
block: add BlockDevOps->drain_threads_cb()
virtio-blk: implement BlockDevOps->drain_threads_cb()
block: add thread_aio_context TLS variable
block: drop bdrv_get_aio_context()
main-loop: use thread-local AioContext
block: disable I/O throttling outside main loop
dataplane: use block layer for I/O
dataplane: drop ioq Linux AIO request queue
block: drop raw_get_aio_fd()
async.c | 2 +
block.c | 22 ++-
block/raw-posix.c | 38 +----
block/raw-win32.c | 2 +-
configure | 21 +++
cpus.c | 2 +
exec.c | 10 +-
hw/block/dataplane/Makefile.objs | 2 +-
hw/block/dataplane/ioq.c | 117 ---------------
hw/block/dataplane/ioq.h | 57 -------
hw/block/dataplane/virtio-blk.c | 290 ++++++++++++------------------------
hw/block/virtio-blk.c | 12 ++
hw/virtio/dataplane/vring.c | 8 +-
include/block/aio.h | 4 +
include/block/block.h | 17 ++-
include/block/block_int.h | 7 -
include/exec/cpu-all.h | 14 +-
include/hw/virtio/dataplane/vring.h | 2 +-
include/qemu/tls.h | 125 +++++++++++++---
main-loop.c | 15 +-
tests/Makefile | 3 +
tests/test-tls.c | 87 +++++++++++
util/qemu-thread-win32.c | 17 +++
23 files changed, 408 insertions(+), 466 deletions(-)
delete mode 100644 hw/block/dataplane/ioq.c
delete mode 100644 hw/block/dataplane/ioq.h
create mode 100644 tests/test-tls.c
--
1.8.1.4
- [Qemu-devel] [RFC 00/13] dataplane: use block layer,
Stefan Hajnoczi <=
- [Qemu-devel] [RFC 01/13] block: fix bdrv_flush() ordering in bdrv_close(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 02/13] dataplane: sync virtio.c and vring.c virtqueue state, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 03/13] block: add BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 04/13] virtio-blk: implement BlockDevOps->drain_threads_cb(), Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 06/13] qemu-thread: add TLS wrappers, Stefan Hajnoczi, 2013/06/14
- [Qemu-devel] [RFC 07/13] block: add thread_aio_context TLS variable, Stefan Hajnoczi, 2013/06/14