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 34804dc42c7a18108126c14c1b5f3d5a9a46f83d..4cbceb1c18dbee75ac5154ff0c15a4e79bd31575 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 { @@ -300,7 +300,7 @@ 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;