Add the ability to specify the min number of threads without changing a gflag

Summary: Add the ability to specify the min number of threads without changing a gflag

Reviewed By: stuclar

Differential Revision: D23557854

fbshipit-source-id: d4394e979c123e7f312816b1dec2849d46b0de9a

folly/executors/IOThreadPoolExecutor.cpp

@@ -94,6 +94,23 @@ IOThreadPoolExecutor::IOThreadPoolExecutor(
   registerThreadPoolExecutor(this);
 }
 
+IOThreadPoolExecutor::IOThreadPoolExecutor(
+    size_t maxThreads,
+    size_t minThreads,
+    std::shared_ptr<ThreadFactory> threadFactory,
+    EventBaseManager* ebm,
+    bool waitForAll)
+    : ThreadPoolExecutor(
+          maxThreads,
+          minThreads,
+          std::move(threadFactory),
+          waitForAll),
+      nextThread_(0),
+      eventBaseManager_(ebm) {
+  setNumThreads(maxThreads);
+  registerThreadPoolExecutor(this);
+}
+
 IOThreadPoolExecutor::~IOThreadPoolExecutor() {
   deregisterThreadPoolExecutor(this);
   stop();

folly/executors/IOThreadPoolExecutor.h

@@ -64,6 +64,14 @@ class IOThreadPoolExecutor : public ThreadPoolExecutor, public IOExecutor {
       folly::EventBaseManager* ebm = folly::EventBaseManager::get(),
       bool waitForAll = false);
 
+  IOThreadPoolExecutor(
+      size_t maxThreads,
+      size_t minThreads,
+      std::shared_ptr<ThreadFactory> threadFactory =
+          std::make_shared<NamedThreadFactory>("IOThreadPool"),
+      folly::EventBaseManager* ebm = folly::EventBaseManager::get(),
+      bool waitForAll = false);
+
   ~IOThreadPoolExecutor() override;
 
   void add(Func func) override;