On Thu, Jan 27, 2011 at 12:56:24PM +0000, Daniel P. Berrange wrote:
> If the event loop takes a very long time todo something, it is
> possible for the 'self pipe' buffer to become full at which
> point the entire event loop + remote driver deadlock. Use a
> boolean flag to ensure we have strict one-in, one-out behaviour
> on writes/reads of the 'self pipe'
> ---
> examples/domain-events/events-python/event-test.py | 10 +++++++++-
> 1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/examples/domain-events/events-python/event-test.py b/examples/domain-events/events-python/event-test.py
> index 903f934..c149ed9 100644
> --- a/examples/domain-events/events-python/event-test.py
> +++ b/examples/domain-events/events-python/event-test.py
> @@ -92,6 +92,8 @@ class virEventLoopPure:
> def __init__(self):
> self.poll = select.poll()
> self.pipetrick = os.pipe()
> + self.pendingWakeup = False
> + self.runningPoll = False
> self.nextHandleID = 1
> self.nextTimerID = 1
> self.handles = []
> @@ -166,6 +168,7 @@ class virEventLoopPure:
> # these pointless repeated tiny sleeps.
> def run_once(self):
> sleep = -1
> + self.runningPoll = True
> next = self.next_timeout()
> debug("Next timeout due at %d" % next)
> if next > 0:
> @@ -184,6 +187,7 @@ class virEventLoopPure:
> # telling us to wakup. if so, then discard
> # the data just continue
> if fd == self.pipetrick[0]:
> + self.pendingWakeup = False
> data = os.read(fd, 1)
> continue
>
> @@ -206,6 +210,8 @@ class virEventLoopPure:
> t.set_last_fired(now)
> t.dispatch()
>
> + self.runningPoll = False
> +
>
> # Actually the event loop forever
> def run_loop(self):
> @@ -214,7 +220,9 @@ class virEventLoopPure:
> self.run_once()
>
> def interrupt(self):
> - os.write(self.pipetrick[1], 'c')
> + if self.runningPoll and not self.pendingWakeup:
> + self.pendingWakeup = True
> + os.write(self.pipetrick[1], 'c')
>
>
> # Registers a new file handle 'fd', monitoring for 'events' (libvirt
ACK,
Daniel
--
Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/
daniel@xxxxxxxxxxxx | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library http://libvirt.org/
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