[Qemu-devel] [RFC] [PATCHv5 00/16] aio / timers: Add AioContext timers and use ppoll

[Alex Bligh <alex@alex.org.uk>]

This patch series adds support for timers attached to an AioContext clock
which get called within aio_poll.

In doing so it removes alarm timers and moves to use ppoll where possible.

This patch set 'sort of' passes make check (see below for caveat)
including a new test harness for the aio timers, but has not been
tested much beyond that. In particular, the win32 changes have not
even been compile tested. Equally, alterations to use_icount
are untested.

Caveat: I have had to alter tests/test-aio.c so the following error
no longer occurs.

ERROR:tests/test-aio.c:346:test_wait_event_notifier_noflush: assertion failed: (aio_poll(ctx, false))

As gar as I can tell, this check was incorrect, in that it checking
aio_poll makes progress when in fact it should not make progress. I
fixed an issue where aio_poll was (as far as I can tell) wrongly
returning true on a timeout, and that generated this error.

Note also the comment on patch 15 in relation to a possible bug
in cpus.c.

Changes since v4:
* Rename qemu_timerlist_ functions to timer_list (per Paolo Bonzini)
* Rename qemu_timer_.*timerlist.* to timer_ (per Paolo Bonzini)
* Use enum for QEMUClockType
* Put clocks into an array; remove global variables
* Introduce QEMUTimerListGroup - a timeliest of each type
* Add a QEMUTimerListGroup to AioContext
* Use a callback on timer modification, rather than binding in
  AioContext into the timeliest
* Make cpus.c iterate over all timerlists when it does a notify
* Make cpus.c icount timeout use soonest timeout
  across all timerlists

Not changed since v4:
* Paolo Bonzini suggested getting rid of the default timerlist
  from the clock. The replacement would be the default AioContext's
  timer lists. I am concerned about the lifetime of the default
  AioContext compared to existing timers that might use the default
  clocks. This could be changed at a later date after code audit.

Changes since v3:
* Split up QEMUClock and QEMUClock list
* Improve commenting
* Fix comment in vl.c
* Change test/test-aio.c to reflect correct behaviour in aio_poll.

Changes since v2:
* Reordered to remove alarm timers last
* Added prctl(PR_SET_TIMERSLACK, 1, ...)
* Renamed qemu_g_poll_ns to qemu_poll_ns
* Moved declaration of above & drop glib types
* Do not use a global list of qemu clocks
* Add AioContext * to QEMUClock
* Split up conversion to use ppoll and timers
* Indentation fix
* Fix aio_win32.c aio_poll to return progress
* aio_notify / qemu_notify when timers are modified
* change comment in deprecation of clock options

Alex Bligh (16):
  aio / timers: add qemu-timer.c utility functions
  aio / timers: add ppoll support with qemu_poll_ns
  aio / timers: Add prctl(PR_SET_TIMERSLACK, 1, ...) to reduce timer
    slack
  aio / timers: Make qemu_run_timers and qemu_run_all_timers return
    progress
  aio / timers: Split QEMUClock into QEMUClock and QEMUTimerList
  aio / timers: Untangle include files
  aio / timers: Add QEMUTimerListGroup and helper functions
  aio / timers: Add QEMUTimerListGroup to AioContext
  aio / timers: Add a notify callback to QEMUTimerList
  aio / timers: aio_ctx_prepare sets timeout from AioContext timers
  aio / timers: Convert aio_poll to use AioContext timers' deadline
  aio / timers: Convert mainloop to use timeout
  aio / timers: On timer modification, qemu_notify or aio_notify
  aio / timers: Use all timerlists in icount warp calculations
  aio / timers: Remove alarm timers
  aio / timers: Add test harness for AioContext timers

 aio-posix.c               |   20 +-
 aio-win32.c               |   22 +-
 async.c                   |   20 +-
 configure                 |   37 +++
 cpus.c                    |   44 ++-
 dma-helpers.c             |    1 +
 hw/dma/xilinx_axidma.c    |    1 +
 hw/timer/arm_timer.c      |    1 +
 hw/timer/grlib_gptimer.c  |    2 +
 hw/timer/imx_epit.c       |    1 +
 hw/timer/imx_gpt.c        |    1 +
 hw/timer/lm32_timer.c     |    1 +
 hw/timer/puv3_ost.c       |    1 +
 hw/timer/slavio_timer.c   |    1 +
 hw/timer/xilinx_timer.c   |    1 +
 hw/usb/hcd-uhci.c         |    1 +
 include/block/aio.h       |    4 +
 include/block/block_int.h |    1 +
 include/block/coroutine.h |    2 +
 include/qemu/timer.h      |  122 ++++++-
 main-loop.c               |   49 ++-
 migration-exec.c          |    1 +
 migration-fd.c            |    1 +
 migration-tcp.c           |    1 +
 migration-unix.c          |    1 +
 migration.c               |    1 +
 nbd.c                     |    1 +
 net/net.c                 |    1 +
 net/socket.c              |    1 +
 qemu-coroutine-io.c       |    1 +
 qemu-io-cmds.c            |    1 +
 qemu-nbd.c                |    1 +
 qemu-timer.c              |  803 ++++++++++++++++-----------------------------
 slirp/misc.c              |    1 +
 tests/test-aio.c          |  141 +++++++-
 tests/test-thread-pool.c  |    3 +
 thread-pool.c             |    1 +
 ui/vnc-auth-vencrypt.c    |    2 +-
 ui/vnc-ws.c               |    1 +
 vl.c                      |    4 +-
 40 files changed, 736 insertions(+), 564 deletions(-)

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1.7.9.5