[RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

[Paolo Bonzini]

ARM machines and other weakly-ordered architectures have been suffering
for a long time from hangs in qemu-img and qemu-io.  For QEMU binaries
these are mitigated by the timers that sooner or later fire in the main
loop, but these will not happen for the tools and probably not with I/O
threads either.

The fix is in patch 5.  Patch 1-3 are docs updates that explain the bug,
and patch 4 is a bugfix exposed by the new patch.

Paolo

Paolo Bonzini (5):
  atomics: convert to reStructuredText
  atomics: update documentation
  rcu: do not mention atomic_mb_read/set in documentation
  aio-wait: delegate polling of main AioContext if BQL not held
  async: use explicit memory barriers

 docs/devel/atomics.rst   | 501 +++++++++++++++++++++++++++++++++++++++
 docs/devel/atomics.txt   | 403 -------------------------------
 docs/devel/index.rst     |   1 +
 docs/devel/rcu.txt       |   4 +-
 include/block/aio-wait.h |  22 ++
 include/block/aio.h      |  29 +--
 util/aio-posix.c         |  16 +-
 util/aio-win32.c         |  17 +-
 util/async.c             |  16 +-
 9 files changed, 576 insertions(+), 433 deletions(-)
 create mode 100644 docs/devel/atomics.rst
 delete mode 100644 docs/devel/atomics.txt

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2.18.2