From: jsimomaa <jani.simomaa@gmail.com>
Date: Thu, 20 Jul 2017 06:53:12 +0000 (+0300)
Subject: Uncommon Acorn deadlock fix
X-Git-Tag: v1.31.0~264^2~46
X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=commitdiff_plain;h=refs%2Fchanges%2F32%2F732%2F2

Uncommon Acorn deadlock fix

refs #7373

Change-Id: Ica31908fca0b70da87bbcf75deb2476bdf305cde
---

diff --git a/bundles/org.simantics.acorn/src/org/simantics/acorn/MainProgram.java b/bundles/org.simantics.acorn/src/org/simantics/acorn/MainProgram.java
index 450ad0618..c69c7bea6 100644
--- a/bundles/org.simantics.acorn/src/org/simantics/acorn/MainProgram.java
+++ b/bundles/org.simantics.acorn/src/org/simantics/acorn/MainProgram.java
@@ -20,9 +20,13 @@ import org.simantics.acorn.lru.ClusterStreamChunk;
 import org.simantics.acorn.lru.ClusterUpdateOperation;
 import org.simantics.db.service.ClusterUID;
 import org.simantics.utils.logging.TimeLogger;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class MainProgram implements Runnable, Closeable {
 
+	private static final Logger LOGGER = LoggerFactory.getLogger(MainProgram.class);
+	
 	private static final int CLUSTER_THREADS = 4;
 	private static final int CHUNK_CACHE_SIZE = 100;
 
@@ -260,14 +264,32 @@ public class MainProgram implements Runnable, Closeable {
 
 	public Exception runIdle(MainProgramRunnable runnable) {
 		try {
-			mutex.acquire();
-			runnable.run();
-			return null;
-		} catch (Exception e) {
-			return e;
+			long startTime = System.currentTimeMillis();
+			while (true) {
+				boolean hasMutex = false;
+				try {
+					synchronized (MainProgram.this) {
+						if (hasMutex = mutex.tryAcquire()) {
+							if (operations.isEmpty()) {
+								runnable.run();
+								return null;
+							}
+						}
+					}
+					long endTime = System.currentTimeMillis(); 
+					if ((endTime - startTime) > 100) {
+						startTime = endTime; 
+						LOGGER.info("MainProgram.runIdle() retry mutex acquire!");
+					}
+				} catch (Exception e) {
+					return e;
+				} finally {
+					if (hasMutex)
+						mutex.release();
+				}
+			}
 		} finally {
 			runnable.done();
-			mutex.release();
 		}
 	}
 	
@@ -297,7 +319,7 @@ public class MainProgram implements Runnable, Closeable {
 
 		ClusterStreamChunk last = operations.isEmpty() ? null : operations.getLast();
         if (!alive) {
-            System.err.println("Trying to commit operation after MainProgram is closed! Operation is " + last);
+            LOGGER.error("Trying to commit operation after MainProgram is closed! Operation is " + last);
 //          return;
         }
 		if(last != null) last.commit();
@@ -306,7 +328,7 @@ public class MainProgram implements Runnable, Closeable {
 
 	public synchronized void schedule(ClusterUpdateOperation operation) throws IllegalAcornStateException {
 	    if (!alive) {
-	        System.err.println("Trying to schedule operation after MainProgram is closed! Operation is " + operation);
+	        LOGGER.error("Trying to schedule operation after MainProgram is closed! Operation is " + operation);
 //	        return;
 	    }
 		clusters.streamLRU.acquireMutex();