Move isWaitForAll_ from ThreadPoolExecutor to IOThreadPoolExecutor

Summary:
I randomly ran into this while working on something else: ThreadPoolExecutor has a field `isWaitForAll_` which:
* is only used in its subclass, `IOThreadPoolExecutor`
* has a comment referencing evbs, which ThreadPoolExecutor doesn't have relationship to but the subclass does.

Looks like this is an artefact of some old refactoring

Reviewed By: yfeldblum

Differential Revision: D31117228

fbshipit-source-id: ea7d1753a0d75ab8911cec68f3b6fb8c1f07c569

folly/executors/IOThreadPoolExecutor.cpp

@@ -86,8 +86,8 @@ IOThreadPoolExecutor::IOThreadPoolExecutor(
     : ThreadPoolExecutor(
           numThreads,
           FLAGS_dynamic_iothreadpoolexecutor ? 0 : numThreads,
-          std::move(threadFactory),
-          waitForAll),
+          std::move(threadFactory)),
+      isWaitForAll_(waitForAll),
       nextThread_(0),
       eventBaseManager_(ebm) {
   setNumThreads(numThreads);
@@ -100,8 +100,8 @@ IOThreadPoolExecutor::IOThreadPoolExecutor(
     std::shared_ptr<ThreadFactory> threadFactory,
     EventBaseManager* ebm,
     bool waitForAll)
-    : ThreadPoolExecutor(
-          maxThreads, minThreads, std::move(threadFactory), waitForAll),
+    : ThreadPoolExecutor(maxThreads, minThreads, std::move(threadFactory)),
+      isWaitForAll_(waitForAll),
       nextThread_(0),
       eventBaseManager_(ebm) {
   setNumThreads(maxThreads);

folly/executors/IOThreadPoolExecutor.h

@@ -102,6 +102,7 @@ class IOThreadPoolExecutor : public ThreadPoolExecutor, public IOExecutor {
   void stopThreads(size_t n) override;
   size_t getPendingTaskCountImpl() const override final;
 
+  const bool isWaitForAll_; // whether to wait till event base loop exits
   std::atomic<size_t> nextThread_;
   folly::ThreadLocal<std::shared_ptr<IOThread>> thisThread_;
   folly::EventBaseManager* eventBaseManager_;

folly/executors/ThreadPoolExecutor.cpp

@@ -48,10 +48,8 @@ DEFINE_int64(
 ThreadPoolExecutor::ThreadPoolExecutor(
     size_t /* maxThreads */,
     size_t minThreads,
-    std::shared_ptr<ThreadFactory> threadFactory,
-    bool isWaitForAll)
+    std::shared_ptr<ThreadFactory> threadFactory)
     : threadFactory_(std::move(threadFactory)),
-      isWaitForAll_(isWaitForAll),
       taskStatsCallbacks_(std::make_shared<TaskStatsCallbackRegistry>()),
       threadPoolHook_("folly::ThreadPoolExecutor"),
       minThreads_(minThreads),

folly/executors/ThreadPoolExecutor.h

@@ -69,8 +69,7 @@ class ThreadPoolExecutor : public DefaultKeepAliveExecutor {
   explicit ThreadPoolExecutor(
       size_t maxThreads,
       size_t minThreads,
-      std::shared_ptr<ThreadFactory> threadFactory,
-      bool isWaitForAll = false);
+      std::shared_ptr<ThreadFactory> threadFactory);
 
   ~ThreadPoolExecutor() override;
 
@@ -287,7 +286,6 @@ class ThreadPoolExecutor : public DefaultKeepAliveExecutor {
 
   std::shared_ptr<ThreadFactory> threadFactory_;
   std::string namePrefix_;
-  const bool isWaitForAll_; // whether to wait till event base loop exits
 
   ThreadList threadList_;
   SharedMutex threadListLock_;