Retry pidControlLoop in individual context handler
io.context is non-preemptive on single thread, which means if all
restartControlLoops are scheduled within one handler, the resources
which are held by pidControlLoop will never be released even given that
their contexts have been cancelled, since their contexts cannot preempt
the context of restartControlLoops.
We need to schedule restartControlLoops in individual context handlers.
Thus when cancellation signal is broadcasted, context runtime will be
yield from restartControlLoops to pidControlLoop to release resources.
Tested:
With multiple reboot cycle (2 machines with 10 reboot cycle with
interval of 10 min), swampd is stable and functional.
Change-Id: I0c750dcfe73016b71c6cfd693c4f8ed99b12e5d0
Signed-off-by: Hao Jiang <jianghao@google.com>
diff --git a/main.cpp b/main.cpp
index 9a47a00..1cd6244 100644
--- a/main.cpp
+++ b/main.cpp
@@ -87,6 +87,11 @@
timer->cancel();
}
timers.clear();
+
+ if (zones.size() > 0 && zones.begin()->second.use_count() > 1)
+ {
+ throw std::runtime_error("wait for count back to 1");
+ }
zones.clear();
const std::string& path =
@@ -139,28 +144,60 @@
}
}
-void tryRestartControlLoops()
+void tryRestartControlLoops(bool first)
{
- int count = 0;
- for (count = 0; count <= 5; count++)
+ static int count = 0;
+ static const auto initialStartTime = std::chrono::milliseconds(10);
+ static const auto delayTeime = std::chrono::seconds(10);
+ static boost::asio::steady_timer timer(io);
+ // try to start a control loop while the loop has been scheduled.
+ if (first && count != 0)
{
- try
- {
- restartControlLoops();
- break;
- }
- catch (const std::exception& e)
- {
- std::cerr << count
- << " Failed during restartControlLoops, try again: "
- << e.what() << "\n";
- if (count >= 5)
- {
- throw std::runtime_error(e.what());
- }
- }
- std::this_thread::sleep_for(std::chrono::seconds(10));
+ std::cerr
+ << "ControlLoops has been scheduled, refresh the loop count\n";
+ count = 1;
+ return;
}
+ // first time of trying to restart the control loop, delay for a small
+ // amount of time.
+ else if (first)
+ {
+ timer.expires_after(initialStartTime);
+ }
+ // re-try control loop, set up a delay.
+ else
+ {
+ timer.expires_after(delayTeime);
+ }
+ count++;
+ timer.async_wait(
+ [](const boost::system::error_code& error) {
+ if (error == boost::asio::error::operation_aborted)
+ {
+ return;
+ }
+ try
+ {
+ restartControlLoops();
+ // reset count after succesful restartControlLoops()
+ count = 0;
+ }
+ catch (const std::exception& e)
+ {
+ if (count >= 5)
+ {
+ std::cerr
+ << "Failed to restartControlLoops after multiple tries"
+ << std::endl;
+ throw std::runtime_error(e.what());
+ }
+
+ std::cerr << count
+ << " Failed during restartControlLoops, try again: "
+ << e.what() << "\n";
+ tryRestartControlLoops(false);
+ }
+ });
return;
}