Share the main thread queue for AsyncChunkProvider

fixes an issue in which thread requests are only processed
for the current provider which can cause a deadlock should
multiple requests exist across providers
This commit is contained in:
Shane Freeder 2018-10-12 15:41:15 +01:00
parent 69a4a30e47
commit 35fcc2e2d0
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GPG Key ID: A3F61EA5A085289C

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@ -1,4 +1,4 @@
From 1248921187e1c418988fe86a9e28b2ae810a092f Mon Sep 17 00:00:00 2001
From 662563828cc23dfd798fb73fac09c21be18cce82 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sat, 21 Jul 2018 16:55:04 -0400
Subject: [PATCH] Async Chunk Loading and Generation
@ -904,7 +904,7 @@ index 98d182fdb8..487d98eb1b 100644
diff --git a/src/main/java/net/minecraft/server/PaperAsyncChunkProvider.java b/src/main/java/net/minecraft/server/PaperAsyncChunkProvider.java
new file mode 100644
index 0000000000..4fc5fad09e
index 0000000000..5823917a65
--- /dev/null
+++ b/src/main/java/net/minecraft/server/PaperAsyncChunkProvider.java
@@ -0,0 +1,593 @@
@ -959,14 +959,14 @@ index 0000000000..4fc5fad09e
+
+ private static final PriorityQueuedExecutor EXECUTOR = new PriorityQueuedExecutor("PaperChunkLoader", PaperConfig.asyncChunks ? PaperConfig.asyncChunkLoadThreads : 0);
+ private static final PriorityQueuedExecutor SINGLE_GEN_EXECUTOR = new PriorityQueuedExecutor("PaperChunkGenerator", PaperConfig.asyncChunks && PaperConfig.asyncChunkGeneration && !PaperConfig.asyncChunkGenThreadPerWorld ? 1 : 0);
+ private static final ConcurrentLinkedQueue<Runnable> MAIN_THREAD_QUEUE = new ConcurrentLinkedQueue<>();
+ private static final ThreadLocal<Boolean> IS_CHUNK_THREAD = ThreadLocal.withInitial(() -> false);
+ private static final ThreadLocal<Boolean> IS_CHUNK_GEN_THREAD = ThreadLocal.withInitial(() -> false);
+
+ private final PriorityQueuedExecutor generationExecutor;
+ //private static final PriorityQueuedExecutor generationExecutor = new PriorityQueuedExecutor("PaperChunkGen", 1);
+ private final Long2ObjectMap<PendingChunk> pendingChunks = Long2ObjectMaps.synchronize(new Long2ObjectOpenHashMap<>());
+ private final ConcurrentLinkedQueue<Runnable> mainThreadQueue = new ConcurrentLinkedQueue<>();
+ private final IAsyncTaskHandler asyncHandler;
+ private final ThreadLocal<Boolean> isChunkThread = ThreadLocal.withInitial(() -> false);
+ private final ThreadLocal<Boolean> isChunkGenThread = ThreadLocal.withInitial(() -> false);
+
+ private final WorldServer world;
+ private final IChunkLoader chunkLoader;
@ -1007,7 +1007,7 @@ index 0000000000..4fc5fad09e
+ private boolean processChunkLoads() {
+ Runnable run;
+ boolean hadLoad = false;
+ while ((run = mainThreadQueue.poll()) != null) {
+ while ((run = MAIN_THREAD_QUEUE.poll()) != null) {
+ run.run();
+ hadLoad = true;
+ }
@ -1071,7 +1071,7 @@ index 0000000000..4fc5fad09e
+ // Listen for when result is ready
+ final CompletableFuture<Chunk> future = new CompletableFuture<>();
+ PendingChunkRequest request = pending.addListener(future, gen);
+ if (isChunkThread.get()) {
+ if (IS_CHUNK_THREAD.get()) {
+ pending.loadTask.run();
+ }
+
@ -1085,7 +1085,7 @@ index 0000000000..4fc5fad09e
+ try (co.aikar.timings.Timing timing = world.timings.syncChunkLoadTimer.startTiming()) {
+ while (!future.isDone()) {
+ // We aren't done, obtain lock on queue
+ synchronized (mainThreadQueue) {
+ synchronized (MAIN_THREAD_QUEUE) {
+ // We may of received our request now, check it
+ if (processChunkLoads()) {
+ // If we processed SOMETHING, don't wait
@ -1093,7 +1093,7 @@ index 0000000000..4fc5fad09e
+ }
+ try {
+ // We got nothing from the queue, wait until something has been added
+ mainThreadQueue.wait(1);
+ MAIN_THREAD_QUEUE.wait(1);
+ } catch (InterruptedException ignored) {
+ }
+ }
@ -1254,8 +1254,8 @@ index 0000000000..4fc5fad09e
+ }
+
+ private Chunk generateChunkExecutor() {
+ isChunkThread.set(true);
+ isChunkGenThread.set(true);
+ IS_CHUNK_THREAD.set(true);
+ IS_CHUNK_GEN_THREAD.set(true);
+ return generateChunk();
+ }
+ private Chunk generateChunk() {
@ -1347,9 +1347,9 @@ index 0000000000..4fc5fad09e
+
+ // Don't post here, even if on main, it must enter the queue so we can exit any open batch
+ // schedulers, as post stage may trigger a new generation and cause errors
+ synchronized (mainThreadQueue) {
+ mainThreadQueue.add(this::postChunk);
+ mainThreadQueue.notify();
+ synchronized (MAIN_THREAD_QUEUE) {
+ MAIN_THREAD_QUEUE.add(this::postChunk);
+ MAIN_THREAD_QUEUE.notify();
+ }
+ }
+
@ -1421,7 +1421,7 @@ index 0000000000..4fc5fad09e
+ genTask = generationExecutor.createPendingTask(this::generateChunkExecutor, taskPriority);
+ }
+ loadTask = EXECUTOR.createPendingTask(this, taskPriority);
+ if (!isChunkThread.get()) {
+ if (!IS_CHUNK_THREAD.get()) {
+ // We will execute it outside of the synchronized context immediately after
+ EXECUTOR.submitTask(loadTask);
+ }
@ -1432,7 +1432,7 @@ index 0000000000..4fc5fad09e
+
+ @Override
+ public void run() {
+ isChunkThread.set(true);
+ IS_CHUNK_THREAD.set(true);
+ try {
+ if (!loadFinished(loadChunk(x, z))) {
+ return;
@ -1448,13 +1448,13 @@ index 0000000000..4fc5fad09e
+ if (shouldGenSync) {
+ synchronized (this) {
+ setStatus(PendingStatus.GENERATION_PENDING);
+ mainThreadQueue.add(() -> generateFinished(this.generateChunk()));
+ MAIN_THREAD_QUEUE.add(() -> generateFinished(this.generateChunk()));
+ }
+ synchronized (mainThreadQueue) {
+ mainThreadQueue.notify();
+ synchronized (MAIN_THREAD_QUEUE) {
+ MAIN_THREAD_QUEUE.notify();
+ }
+ } else {
+ if (isChunkGenThread.get()) {
+ if (IS_CHUNK_GEN_THREAD.get()) {
+ // ideally we should never run into 1 chunk generating another chunk...
+ // but if we do, let's apply same solution
+ genTask.run();