From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Aikar Date: Fri, 29 May 2020 20:29:02 -0400 Subject: [PATCH] Synchronize PalettedContainer instead of ThreadingDetector/Semaphore Mojang has flaws in their logic about chunks being concurrently wrote to. So we constantly see crashes around multiple threads writing. Additionally, java has optimized synchronization so well that its in many times faster than trying to manage read write locks for low contention situations. And this is extremely a low contention situation. diff --git a/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java b/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java index 02b7e3261f689b9d30b87661db23425f741b0fec..715830d27490572bbe963515f046205c6d7e834d 100644 --- a/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java +++ b/src/main/java/net/minecraft/world/level/chunk/PalettedContainer.java @@ -32,14 +32,14 @@ public class PalettedContainer implements PaletteResize, PalettedContainer private final T @org.jetbrains.annotations.Nullable [] presetValues; // Paper - Anti-Xray - Add preset values private volatile PalettedContainer.Data data; private final PalettedContainer.Strategy strategy; - private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer"); + // private final ThreadingDetector threadingDetector = new ThreadingDetector("PalettedContainer"); // Paper - unused public void acquire() { - this.threadingDetector.checkAndLock(); + // this.threadingDetector.checkAndLock(); // Paper - disable this - use proper synchronization } public void release() { - this.threadingDetector.checkAndUnlock(); + // this.threadingDetector.checkAndUnlock(); // Paper - disable this } // Paper start - Anti-Xray - Add preset values @@ -129,7 +129,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer } @Override - public int onResize(int newBits, T object) { + public synchronized int onResize(int newBits, T object) { // Paper - synchronize PalettedContainer.Data data = this.data; // Paper start - Anti-Xray - Add preset values @@ -176,7 +176,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer return this.getAndSet(this.strategy.getIndex(x, y, z), value); } - private T getAndSet(int index, T value) { + private synchronized T getAndSet(int index, T value) { // Paper - synchronize int i = this.data.palette.idFor(value); int j = this.data.storage.getAndSet(index, i); return this.data.palette.valueFor(j); @@ -193,7 +193,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer } - private void set(int index, T value) { + private synchronized void set(int index, T value) { // Paper - synchronize int i = this.data.palette.idFor(value); this.data.storage.set(index, i); } @@ -218,7 +218,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer }); } - public void read(FriendlyByteBuf buf) { + public synchronized void read(FriendlyByteBuf buf) { // Paper - synchronize this.acquire(); try { @@ -238,7 +238,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer @Override @Deprecated @io.papermc.paper.annotation.DoNotUse public void write(FriendlyByteBuf buf) { this.write(buf, null, 0); } @Override - public void write(FriendlyByteBuf buf, @Nullable com.destroystokyo.paper.antixray.ChunkPacketInfo chunkPacketInfo, int bottomBlockY) { + public synchronized void write(FriendlyByteBuf buf, @Nullable com.destroystokyo.paper.antixray.ChunkPacketInfo chunkPacketInfo, int bottomBlockY) { // Paper - synchronize this.acquire(); try { @@ -296,7 +296,7 @@ public class PalettedContainer implements PaletteResize, PalettedContainer } @Override - public PalettedContainerRO.PackedData pack(IdMap idList, PalettedContainer.Strategy paletteProvider) { + public synchronized PalettedContainerRO.PackedData pack(IdMap idList, PalettedContainer.Strategy paletteProvider) { // Paper - synchronize this.acquire(); PalettedContainerRO.PackedData var12;