OS stack memory offloading for VM execution.

libethereum/ExtVM.cpp

@@ -20,18 +20,58 @@
  */
 
 #include "ExtVM.h"
-
+#include <exception>
+#include <boost/thread.hpp>
 #include "Executive.h"
-using namespace std;
+
 using namespace dev;
 using namespace dev::eth;
 
+namespace
+{
+static unsigned const c_depthLimit = 1024;
+static size_t const c_singleExecutionStackSize = 8 * 1024;
+static size_t const c_defaultStackSize = 512 * 1024;
+static unsigned const c_offloadPoint = c_defaultStackSize / c_singleExecutionStackSize;
+
+void goOnOffloadedStack(Executive& _e, OnOpFunc const& _onOp)
+{
+	cnote << "CALL OFFLOADING: offloading point " << c_offloadPoint;
+	boost::thread::attributes attrs;
+	attrs.set_stack_size((c_depthLimit - c_offloadPoint) * c_singleExecutionStackSize);
+
+	std::exception_ptr exception;
+	boost::thread{attrs, [&]{
+		cnote << "OFFLOADING thread";
+		try
+		{
+			_e.go(_onOp);
+		}
+		catch (...)
+		{
+			cnote << "!!!!!!!!!!! exception in offloading!!!!!!!!!!!!";
+			exception = std::current_exception();
+		}
+	}}.join();
+	if (exception)
+		std::rethrow_exception(exception);
+}
+
+void go(unsigned _depth, Executive& _e, OnOpFunc const& _onOp)
+{
+	if (_depth == c_offloadPoint)
+		goOnOffloadedStack(_e, _onOp);
+	else
+		_e.go(_onOp);
+}
+}
+
 bool ExtVM::call(CallParameters& _p)
 {
 	Executive e(m_s, lastHashes, depth + 1);
 	if (!e.call(_p, gasPrice, origin))
 	{
-		e.go(_p.onOp);
+		go(depth, e, _p.onOp);
 		e.accrueSubState(sub);
 	}
 	_p.gas = e.gas();
@@ -47,7 +87,7 @@ h160 ExtVM::create(u256 _endowment, u256& io_gas, bytesConstRef _code, OnOpFunc
 	Executive e(m_s, lastHashes, depth + 1);
 	if (!e.create(myAddress, _endowment, gasPrice, io_gas, _code, origin))
 	{
-		e.go(_onOp);
+		go(depth, e, _onOp);
 		e.accrueSubState(sub);
 	}
 	io_gas = e.gas();