Enable increasing/decreasing compute threads.

src/kernel/Executor.cc

@@ -52,12 +52,6 @@ void ExecQueue::deinit()
 
 int Executor::init(size_t nthreads)
 {
-	if (nthreads == 0)
-	{
-		errno = EINVAL;
-		return -1;
-	}
-
 	this->thrdpool = thrdpool_create(nthreads, 0);
 	if (this->thrdpool)
 		return 0;
@@ -152,3 +146,13 @@ int Executor::request(ExecSession *session, ExecQueue *queue)
 	return -!entry;
 }
 
+int Executor::increase_thread()
+{
+	return thrdpool_increase(this->thrdpool);
+}
+
+int Executor::decrease_thread()
+{
+	return thrdpool_decrease(this->thrdpool);
+}
+

src/kernel/Executor.h

@@ -67,6 +67,10 @@ public:
 
 	int request(ExecSession *session, ExecQueue *queue);
 
+public:
+	int increase_thread();
+	int decrease_thread();
+
 private:
 	struct __thrdpool *thrdpool;
 

src/manager/WFGlobal.cc

@@ -421,7 +421,7 @@ private:
 	{
 		int compute_threads = WFGlobal::get_global_settings()->compute_threads;
 
-		if (compute_threads <= 0)
+		if (compute_threads < 0)
 			compute_threads = sysconf(_SC_NPROCESSORS_ONLN);
 
 		if (compute_executor_.init(compute_threads) < 0)

src/manager/WFGlobal.h

@@ -54,7 +54,7 @@ struct WFGlobalSettings
 	int dns_threads;
 	int poller_threads;
 	int handler_threads;
-	int compute_threads;			///< auto-set by system CPU number if value<=0
+	int compute_threads;			///< auto-set by system CPU number if value<0
 	int fio_max_events;
 	const char *resolv_conf_path;
 	const char *hosts_path;
@@ -124,6 +124,16 @@ public:
 
 	static const char *get_error_string(int state, int error);
 
+	static bool increase_compute_thread()
+	{
+		return WFGlobal::get_compute_executor()->increase_thread() == 0;
+	}
+
+	static bool decrease_compute_thread()
+	{
+		return WFGlobal::get_compute_executor()->decrease_thread() == 0;
+	}
+
 	// Internal usage only
 public:
 	static bool is_scheduler_created();