On Mon, Jan 20, 2020 at 10:35:33AM +0000, Stefan Hajnoczi wrote:
> On Tue, Jan 14, 2020 at 10:59:06AM +0000, Stefan Hajnoczi wrote:
> > v13:
> > * Drop unnecessary changes in Patch 8 [Stefano]
> >
> > 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 | 85 +++++--
> > 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, 787 insertions(+), 72 deletions(-)
> > create mode 100644 block/io_uring.c
> > create mode 100644 stubs/io_uring.c
> >
> > --
> > 2.24.1
> >
> >
>
> Thanks, applied to my block tree:
> https://github.com/stefanha/qemu/commits/block
Kevin Wolf pointed out that BDRV_O_IO_URING isn't used by this series!
Oops, that means io_uring.c isn't being called anymore. This bug
slipped in as part of v3. I've sent a new revision.
Stefan