fix job consume (possible deadlock)

fix #1505

- fix possible deadlock of the executor thread
- fix racecondition during the job consumation
- remove switch_work in all classes `minethd`
- move `consume_work` into `globalStates`

1 files changed, 5 insertions, 25 deletions

diff --git a/xmrstak/backend/nvidia/minethd.cpp b/xmrstak/backend/nvidia/minethd.cpp
index d14fbd4..05ee0c6 100644
--- a/xmrstak/backend/nvidia/minethd.cpp
+++ b/xmrstak/backend/nvidia/minethd.cpp
@@ -195,27 +195,6 @@ std::vector<iBackend*>* minethd::thread_starter(uint32_t threadOffset, miner_wor
 	return pvThreads;
 }
 
-void minethd::switch_work(miner_work& pWork)
-{
-	// iConsumeCnt is a basic lock-like polling mechanism just in case we happen to push work
-	// faster than threads can consume them. This should never happen in real life.
-	// Pool cant physically send jobs faster than every 250ms or so due to net latency.
-
-	while (globalStates::inst().iConsumeCnt.load(std::memory_order_seq_cst) < globalStates::inst().iThreadCount)
-		std::this_thread::sleep_for(std::chrono::milliseconds(100));
-
-	globalStates::inst().oGlobalWork = pWork;
-	globalStates::inst().iConsumeCnt.store(0, std::memory_order_seq_cst);
-	globalStates::inst().iGlobalJobNo++;
-}
-
-void minethd::consume_work()
-{
-	memcpy(&oWork, &globalStates::inst().oGlobalWork, sizeof(miner_work));
-	iJobNo++;
-	globalStates::inst().iConsumeCnt++;
-}
-
 void minethd::work_main()
 {
 	if(affinity >= 0) //-1 means no affinity
@@ -244,8 +223,6 @@ void minethd::work_main()
 
 	uint32_t iNonce;
 
-	globalStates::inst().iConsumeCnt++;
-
 	uint8_t version = 0;
 	size_t lastPoolId = 0;
 
@@ -261,7 +238,7 @@ void minethd::work_main()
 			while (globalStates::inst().iGlobalJobNo.load(std::memory_order_relaxed) == iJobNo)
 				std::this_thread::sleep_for(std::chrono::milliseconds(100));
 
-			consume_work();
+			globalStates::inst().consume_work(oWork, iJobNo);
 			continue;
 		}
 		uint8_t new_version = oWork.getVersion();
@@ -299,6 +276,9 @@ void minethd::work_main()
 			{
 				globalStates::inst().calc_start_nonce(iNonce, oWork.bNiceHash, h_per_round * 16);
 			}
+			// check if the job is still valid, there is a small posibility that the job is switched
+			if(globalStates::inst().iGlobalJobNo.load(std::memory_order_relaxed) != iJobNo)
+				break;
 
 			uint32_t foundNonce[10];
 			uint32_t foundCount;
@@ -337,7 +317,7 @@ void minethd::work_main()
 			std::this_thread::yield();
 		}
 
-		consume_work();
+		globalStates::inst().consume_work(oWork, iJobNo);
 	}
 }