The series LGTM, just some comments on patches 4 and 8.
I succefully tried iotests on raw and qcow2 with io_uring, so
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Thanks,
Stefano
On Wed, Dec 18, 2019 at 04:32:13PM +0000, Stefan Hajnoczi wrote:
> v12:
> * Reword BlockdevAioOptions QAPI schema commit description [Markus]
> * Increase QAPI "Since: 4.2" to "Since: 5.0"
> * Explain rationale for io_uring stubs in commit description [Kevin]
> * Tried to use file.aio=io_uring instead of BDRV_O_IO_URING but it's really
> hard to make qemu-iotests work. Tests build blkdebug: and other graphs so
> the syntax for io_uring is dependent on the test case. I scrapped this
> approach and went back to a global flag.
>
> v11:
> * Drop fd registration because it breaks QEMU's file locking and will need to
> be resolved in a separate patch series
> * Drop line-wrapping changes that accidentally broke several qemu-iotests
>
> v10:
> * Dropped kernel submission queue polling, it requires root and has additional
> limitations. It should be benchmarked and considered for inclusion later,
> maybe even together with kernel side changes.
> * Add io_uring_register_files() return value to trace_luring_fd_register()
> * Fix indentation in luring_fd_unregister()
> * Set s->fd_reg.fd_array to NULL after g_free() to avoid dangling pointers
> * Simplify fd registration code
> * Add luring_fd_unregister() and call it from file-posix.c to prevent
> fd leaks
> * Add trace_luring_fd_unregister() trace event
> * Add missing space to qemu-img command-line documentation
> * Update MAINTAINERS file [Julia]
> * Rename MAX_EVENTS to MAX_ENTRIES [Julia]
> * Define ioq_submit() before callers so the prototype isn't necessary [Julia]
> * Declare variables at the beginning of the block in luring_init() [Julia]
>
> This patch series is based on Aarushi Mehta's v9 patch series written for
> Google Summer of Code 2019:
>
> https://lists.gnu.org/archive/html/qemu-devel/2019-08/msg00179.html
>
> It adds a new AIO engine that uses the new Linux io_uring API. This is the
> successor to Linux AIO with a number of improvements:
> 1. Both O_DIRECT and buffered I/O work
> 2. fdatasync(2) is supported (no need for a separate thread pool!)
> 3. True async behavior so the syscall doesn't block (Linux AIO got there to some degree...)
> 4. Advanced performance optimizations are available (file registration, memory
> buffer registration, completion polling, submission polling).
>
> Since Aarushi has been busy, I have taken up this patch series. Booting a
> guest works with -drive aio=io_uring and -drive aio=io_uring,cache=none with a
> raw file on XFS.
>
> I currently recommend using -drive aio=io_uring only with host block devices
> (like NVMe devices). As of Linux v5.4-rc1 I still hit kernel bugs when using
> image files on ext4 or XFS.
>
> Aarushi Mehta (15):
> configure: permit use of io_uring
> qapi/block-core: add option for io_uring
> block/block: add BDRV flag for io_uring
> block/io_uring: implements interfaces for io_uring
> stubs: add stubs for io_uring interface
> util/async: add aio interfaces for io_uring
> blockdev: adds bdrv_parse_aio to use io_uring
> block/file-posix.c: extend to use io_uring
> block: add trace events for io_uring
> block/io_uring: adds userspace completion polling
> qemu-io: adds option to use aio engine
> qemu-img: adds option to use aio engine for benchmarking
> qemu-nbd: adds option for aio engines
> tests/qemu-iotests: enable testing with aio options
> tests/qemu-iotests: use AIOMODE with various tests
>
> MAINTAINERS | 9 +
> block.c | 22 ++
> block/Makefile.objs | 3 +
> block/file-posix.c | 95 ++++++--
> block/io_uring.c | 433 ++++++++++++++++++++++++++++++++++
> block/trace-events | 12 +
> blockdev.c | 12 +-
> configure | 27 +++
> include/block/aio.h | 16 +-
> include/block/block.h | 2 +
> include/block/raw-aio.h | 12 +
> qapi/block-core.json | 4 +-
> qemu-img-cmds.hx | 4 +-
> qemu-img.c | 11 +-
> qemu-img.texi | 5 +-
> qemu-io.c | 25 +-
> qemu-nbd.c | 12 +-
> qemu-nbd.texi | 4 +-
> stubs/Makefile.objs | 1 +
> stubs/io_uring.c | 32 +++
> tests/qemu-iotests/028 | 2 +-
> tests/qemu-iotests/058 | 2 +-
> tests/qemu-iotests/089 | 4 +-
> tests/qemu-iotests/091 | 4 +-
> tests/qemu-iotests/109 | 2 +-
> tests/qemu-iotests/147 | 5 +-
> tests/qemu-iotests/181 | 8 +-
> tests/qemu-iotests/183 | 4 +-
> tests/qemu-iotests/185 | 10 +-
> tests/qemu-iotests/200 | 2 +-
> tests/qemu-iotests/201 | 8 +-
> tests/qemu-iotests/check | 15 +-
> tests/qemu-iotests/common.rc | 14 ++
> tests/qemu-iotests/iotests.py | 12 +-
> util/async.c | 36 +++
> 35 files changed, 793 insertions(+), 76 deletions(-)
> create mode 100644 block/io_uring.c
> create mode 100644 stubs/io_uring.c
>
> --
> 2.23.0
>
>