Paper/patches/server/0532-Fix-Concurrency-issue-in-WeightedList.patch
Shane Freeder aa52bf9e33
Remove "Implement-Chunk-Priority-Urgency-System-for-Chunks" (Fixes #5980)
Mojang made some changes to priorities in 1.17 and it seems that these changes
conflict with the changes made in this patch, which in some cases appears to
cause excessive rescheduling of tasks.

This, however, is not confirmed as such but seems to be the behavior that we're
seeing to cause this issue, if mojang has adopted the changes we suggested,
then a good chunk of this patch may be unneeded, but, this needs a much better
look than I'm currently able to do
2021-08-14 14:55:55 +01:00

70 Zeilen
3.5 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Mon, 6 Jul 2020 18:36:41 -0400
Subject: [PATCH] Fix Concurrency issue in WeightedList
if multiple threads from worldgen sort at same time, it will crash.
So make a copy of the list for sorting purposes.
diff --git a/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java b/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
index 893c37cc7e33f4baa98131afca45a258600ddc75..09998d160a6d79fdb5a5041a5d572649a1532e6a 100644
--- a/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
+++ b/src/main/java/net/minecraft/world/entity/ai/behavior/GateBehavior.java
@@ -16,7 +16,7 @@ public class GateBehavior<E extends LivingEntity> extends Behavior<E> {
private final Set<MemoryModuleType<?>> exitErasedMemories;
private final GateBehavior.OrderPolicy orderPolicy;
private final GateBehavior.RunningPolicy runningPolicy;
- private final ShufflingList<Behavior<? super E>> behaviors = new ShufflingList<>();
+ private final ShufflingList<Behavior<? super E>> behaviors = new ShufflingList<>(false); // Paper - don't use a clone
public GateBehavior(Map<MemoryModuleType<?>, MemoryStatus> requiredMemoryState, Set<MemoryModuleType<?>> memoriesToForgetWhenStopped, GateBehavior.OrderPolicy order, GateBehavior.RunningPolicy runMode, List<Pair<Behavior<? super E>, Integer>> tasks) {
super(requiredMemoryState);
diff --git a/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java b/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
index d4c9def80154c3e62a0b6928057062a0808f339f..4fa64b1e2004810906bb0b174436c8e687a75ada 100644
--- a/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
+++ b/src/main/java/net/minecraft/world/entity/ai/behavior/ShufflingList.java
@@ -14,12 +14,25 @@ import java.util.stream.Stream;
public class ShufflingList<U> {
protected final List<ShufflingList.WeightedEntry<U>> entries;
private final Random random = new Random();
+ private final boolean isUnsafe; // Paper
public ShufflingList() {
+ // Paper start
+ this(true);
+ }
+ public ShufflingList(boolean isUnsafe) {
+ this.isUnsafe = isUnsafe;
+ // Paper end
this.entries = Lists.newArrayList();
}
private ShufflingList(List<ShufflingList.WeightedEntry<U>> list) {
+ // Paper start
+ this(list, true);
+ }
+ private ShufflingList(List<ShufflingList.WeightedEntry<U>> list, boolean isUnsafe) {
+ this.isUnsafe = isUnsafe;
+ // Paper end
this.entries = Lists.newArrayList(list);
}
@@ -35,11 +48,12 @@ public class ShufflingList<U> {
}
public ShufflingList<U> shuffle() {
- this.entries.forEach((entry) -> {
- entry.setRandom(this.random.nextFloat());
- });
- this.entries.sort(Comparator.comparingDouble(ShufflingList.WeightedEntry::getRandWeight));
- return this;
+ // Paper start - make concurrent safe, work off a clone of the list
+ List<ShufflingList.WeightedEntry<U>> list = this.isUnsafe ? Lists.newArrayList(this.entries) : this.entries;
+ list.forEach(entry -> entry.setRandom(this.random.nextFloat()));
+ list.sort(Comparator.comparingDouble(ShufflingList.WeightedEntry::getRandWeight));
+ return this.isUnsafe ? new ShufflingList<>(list, this.isUnsafe) : this;
+ // Paper end
}
public Stream<U> stream() {