FiberManager's shutdown only waits for remote tasks to drain

Reviewed By: andriigrynenko

Differential Revision: D26572552

fbshipit-source-id: 035e1313cd4dec070555b5cd41efc58a0b4a948a

folly/fibers/FiberManager.cpp

@@ -118,6 +118,10 @@ bool FiberManager::hasTasks() const {
       !remoteTaskQueue_.empty() || remoteCount_ > 0;
 }
 
+bool FiberManager::isRemoteScheduled() const {
+  return remoteCount_ > 0;
+}
+
 Fiber* FiberManager::getFiber() {
   Fiber* fiber = nullptr;
 

folly/fibers/FiberManagerInternal.h

@@ -219,6 +219,7 @@ class FiberManager : public ::folly::Executor {
    * @return true if there are outstanding tasks.
    */
   bool hasTasks() const;
+  bool isRemoteScheduled() const;
 
   /**
    * @return The number of currently active fibers (ready to run or blocked).

folly/python/fiber_manager.pxd

@@ -25,7 +25,8 @@ cdef extern from "folly/fibers/FiberManagerInternal.h" namespace "folly::fibers"
         pass
     cdef cppclass cFiberManager "folly::fibers::FiberManager":
         cFiberManager(unique_ptr[cLoopController], const cFiberManagerOptions&)
-        bool hasTasks() const
+        void loopUntilNoReady()
+        bool isRemoteScheduled() const
 
 cdef extern from "folly/fibers/ExecutorLoopController.h" namespace "folly::fibers":
     cdef cppclass cAsyncioLoopController "folly::fibers::ExecutorLoopController"(cLoopController):

folly/python/fiber_manager.pyx

@@ -44,9 +44,11 @@ cdef class FiberManager:
             opts));
 
     def __dealloc__(FiberManager self):
-        while deref(self.cManager).hasTasks():
+        while deref(self.cManager).isRemoteScheduled():
             self.cExecutor.drive()
 
+        deref(self.cManager).loopUntilNoReady()
+
         # Explicitly reset here, otherwise it is possible
         # that self.cManager dstor runs after python finalizes
         # Cython deletes these after __dealloc__ returns.