Optimize PlayerChunkMap memory use for visibleChunks

No longer clones visible chunks which is causing massive memory
allocation issues, likely the source of Humongous Objects on large servers.

Instead we just synchronize, clear and rebuild, reusing the same object buffers
as before with only 2 small objects created (FastIterator/MapEntry)

This should result in siginificant memory use reduction and improved GC behavior.
This commit is contained in:
Aikar 2020-04-08 03:09:05 -04:00
parent 6c39a59ae7
commit a65831bd69
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@ -0,0 +1,177 @@
From 38cb54b87993ec1a444f34f2b7f84eac40ef06e0 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 8 Apr 2020 03:06:30 -0400
Subject: [PATCH] Optimize PlayerChunkMap memory use for visibleChunks
No longer clones visible chunks which is causing massive memory
allocation issues, likely the source of Humongous Objects on large servers.
Instead we just synchronize, clear and rebuild, reusing the same object buffers
as before with only 2 small objects created (FastIterator/MapEntry)
This should result in siginificant memory use reduction and improved GC behavior.
diff --git a/src/main/java/net/minecraft/server/ChunkProviderServer.java b/src/main/java/net/minecraft/server/ChunkProviderServer.java
index 1dcd0980ec..59055cccc5 100644
--- a/src/main/java/net/minecraft/server/ChunkProviderServer.java
+++ b/src/main/java/net/minecraft/server/ChunkProviderServer.java
@@ -669,7 +669,7 @@ public class ChunkProviderServer extends IChunkProvider {
entityPlayer.playerNaturallySpawnedEvent.callEvent();
};
// Paper end
- this.playerChunkMap.f().forEach((playerchunk) -> {
+ this.playerChunkMap.visibleChunks.values().forEach((playerchunk) -> { // Paper - no need to wrap iterator
Optional<Chunk> optional = ((Either) playerchunk.b().getNow(PlayerChunk.UNLOADED_CHUNK)).left();
if (optional.isPresent()) {
diff --git a/src/main/java/net/minecraft/server/MCUtil.java b/src/main/java/net/minecraft/server/MCUtil.java
index b9d5844520..9980e4c277 100644
--- a/src/main/java/net/minecraft/server/MCUtil.java
+++ b/src/main/java/net/minecraft/server/MCUtil.java
@@ -500,7 +500,7 @@ public final class MCUtil {
WorldServer world = ((org.bukkit.craftbukkit.CraftWorld)bukkitWorld).getHandle();
PlayerChunkMap chunkMap = world.getChunkProvider().playerChunkMap;
- Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunks = chunkMap.visibleChunks;
+ Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunks = chunkMap.getVisibleChunks();
ChunkMapDistance chunkMapDistance = chunkMap.getChunkMapDistanceManager();
List<PlayerChunk> allChunks = new ArrayList<>(visibleChunks.values());
List<EntityPlayer> players = world.players;
diff --git a/src/main/java/net/minecraft/server/PlayerChunkMap.java b/src/main/java/net/minecraft/server/PlayerChunkMap.java
index e1e4ea793a..0aa6487d5b 100644
--- a/src/main/java/net/minecraft/server/PlayerChunkMap.java
+++ b/src/main/java/net/minecraft/server/PlayerChunkMap.java
@@ -56,7 +56,8 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
private static final Logger LOGGER = LogManager.getLogger();
public static final int GOLDEN_TICKET = 33 + ChunkStatus.b();
public final Long2ObjectLinkedOpenHashMap<PlayerChunk> updatingChunks = new Long2ObjectLinkedOpenHashMap();
- public volatile Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunks;
+ public final Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunks = new Long2ObjectLinkedOpenHashMap(); // Paper - remove copying, make mt safe
+ public transient Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunksClone; // Paper - remove copying, make mt safe
private final Long2ObjectLinkedOpenHashMap<PlayerChunk> pendingUnload;
final LongSet loadedChunks; // Paper - private -> package
public final WorldServer world;
@@ -170,7 +171,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
public PlayerChunkMap(WorldServer worldserver, File file, DataFixer datafixer, DefinedStructureManager definedstructuremanager, Executor executor, IAsyncTaskHandler<Runnable> iasynctaskhandler, ILightAccess ilightaccess, ChunkGenerator<?> chunkgenerator, WorldLoadListener worldloadlistener, Supplier<WorldPersistentData> supplier, int i) {
super(new File(worldserver.getWorldProvider().getDimensionManager().a(file), "region"), datafixer);
- this.visibleChunks = this.updatingChunks.clone();
+ //this.visibleChunks = this.updatingChunks.clone(); // Paper - no more cloning
this.pendingUnload = new Long2ObjectLinkedOpenHashMap();
this.loadedChunks = new LongOpenHashSet();
this.unloadQueue = new LongOpenHashSet();
@@ -262,8 +263,32 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
return (PlayerChunk) this.updatingChunks.get(i);
}
+ // Paper start - remove cloning of visible chunks unless accessed as a collection async
+ private static final boolean DEBUG_ASYNC_VISIBLE_CHUNKS = Boolean.getBoolean("paper.debug-async-visible-chunks");
+ public Long2ObjectLinkedOpenHashMap<PlayerChunk> getVisibleChunks() {
+ if (Thread.currentThread() == this.world.serverThread) {
+ return this.visibleChunks;
+ } else {
+ synchronized (this.visibleChunks) {
+ if (DEBUG_ASYNC_VISIBLE_CHUNKS) new Throwable("Async getVisibleChunks").printStackTrace();
+ if (this.visibleChunksClone == null) {
+ this.visibleChunksClone = this.visibleChunks.clone();
+ }
+ return this.visibleChunksClone;
+ }
+ }
+ }
+ // Paper end
+
@Nullable
public PlayerChunk getVisibleChunk(long i) { // Paper - protected -> public
+ // Paper start - mt safe get
+ if (Thread.currentThread() != this.world.serverThread) {
+ synchronized (this.visibleChunks) {
+ return (PlayerChunk) this.visibleChunks.get(i);
+ }
+ }
+ // Paper end
return (PlayerChunk) this.visibleChunks.get(i);
}
@@ -444,8 +469,9 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
// Paper end
protected void save(boolean flag) {
+ Long2ObjectLinkedOpenHashMap<PlayerChunk> visibleChunks = this.getVisibleChunks(); // Paper remove clone of visible Chunks unless saving off main thread (watchdog kill)
if (flag) {
- List<PlayerChunk> list = (List) this.visibleChunks.values().stream().filter(PlayerChunk::hasBeenLoaded).peek(PlayerChunk::m).collect(Collectors.toList());
+ List<PlayerChunk> list = (List) visibleChunks.values().stream().filter(PlayerChunk::hasBeenLoaded).peek(PlayerChunk::m).collect(Collectors.toList()); // Paper - remove cloning of visible chunks
MutableBoolean mutableboolean = new MutableBoolean();
do {
@@ -473,7 +499,7 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
// this.i(); // Paper - nuke IOWorker
PlayerChunkMap.LOGGER.info("ThreadedAnvilChunkStorage ({}): All chunks are saved", this.w.getName());
} else {
- this.visibleChunks.values().stream().filter(PlayerChunk::hasBeenLoaded).forEach((playerchunk) -> {
+ visibleChunks.values().stream().filter(PlayerChunk::hasBeenLoaded).forEach((playerchunk) -> {
IChunkAccess ichunkaccess = (IChunkAccess) playerchunk.getChunkSave().getNow(null); // CraftBukkit - decompile error
if (ichunkaccess instanceof ProtoChunkExtension || ichunkaccess instanceof Chunk) {
@@ -643,7 +669,14 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
if (!this.updatingChunksModified) {
return false;
} else {
- this.visibleChunks = this.updatingChunks.clone();
+ // Paper start - stop cloning visibleChunks
+ synchronized (this.visibleChunks) {
+ this.visibleChunks.clear();
+ this.visibleChunks.putAll(this.updatingChunks);
+ this.visibleChunksClone = null;
+ }
+ // Paper end
+
this.updatingChunksModified = false;
return true;
}
@@ -1104,12 +1137,12 @@ public class PlayerChunkMap extends IChunkLoader implements PlayerChunk.d {
}
protected Iterable<PlayerChunk> f() {
- return Iterables.unmodifiableIterable(this.visibleChunks.values());
+ return Iterables.unmodifiableIterable(this.getVisibleChunks().values()); // Paper
}
void a(Writer writer) throws IOException {
CSVWriter csvwriter = CSVWriter.a().a("x").a("z").a("level").a("in_memory").a("status").a("full_status").a("accessible_ready").a("ticking_ready").a("entity_ticking_ready").a("ticket").a("spawning").a("entity_count").a("block_entity_count").a(writer);
- ObjectBidirectionalIterator objectbidirectionaliterator = this.visibleChunks.long2ObjectEntrySet().iterator();
+ ObjectBidirectionalIterator objectbidirectionaliterator = this.getVisibleChunks().long2ObjectEntrySet().iterator(); // Paper
while (objectbidirectionaliterator.hasNext()) {
Entry<PlayerChunk> entry = (Entry) objectbidirectionaliterator.next();
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 051506fce8..c0e8eb85d7 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -290,6 +290,7 @@ public class CraftWorld implements World {
return ret;
}
public int getTileEntityCount() {
+ org.spigotmc.AsyncCatcher.catchOp("getTileEntityCount");
// We don't use the full world tile entity list, so we must iterate chunks
Long2ObjectLinkedOpenHashMap<PlayerChunk> chunks = world.getChunkProvider().playerChunkMap.visibleChunks;
int size = 0;
@@ -306,6 +307,7 @@ public class CraftWorld implements World {
return world.tileEntityListTick.size();
}
public int getChunkCount() {
+ org.spigotmc.AsyncCatcher.catchOp("getChunkCount");
int ret = 0;
for (PlayerChunk chunkHolder : world.getChunkProvider().playerChunkMap.visibleChunks.values()) {
@@ -432,6 +434,7 @@ public class CraftWorld implements World {
@Override
public Chunk[] getLoadedChunks() {
+ org.spigotmc.AsyncCatcher.catchOp("getLoadedChunks"); // Paper
Long2ObjectLinkedOpenHashMap<PlayerChunk> chunks = world.getChunkProvider().playerChunkMap.visibleChunks;
return chunks.values().stream().map(PlayerChunk::getFullChunk).filter(Objects::nonNull).map(net.minecraft.server.Chunk::getBukkitChunk).toArray(Chunk[]::new);
}
--
2.25.1