Paper/patches/server/0322-Fix-World-isChunkGenerated-calls.patch
Spottedleaf 01a13871de
Rewrite chunk system (#8177)
Patch documentation to come

Issues with the old system that are fixed now:
- World generation does not scale with cpu cores effectively.
- Relies on the main thread for scheduling and maintaining chunk state, dropping chunk load/generate rates at lower tps.
- Unreliable prioritisation of chunk gen/load calls that block the main thread.
- Shutdown logic is utterly unreliable, as it has to wait for all chunks to unload - is it guaranteed that the chunk system is in a state on shutdown that it can reliably do this? Watchdog shutdown also typically failed due to thread checks, which is now resolved.
- Saving of data is not unified (i.e can save chunk data without saving entity data, poses problems for desync if shutdown is really abnormal.
- Entities are not loaded with chunks. This caused quite a bit of headache for Chunk#getEntities API, but now the new chunk system loads entities with chunks so that they are ready whenever the chunk loads in. Effectively brings the behavior back to 1.16 era, but still storing entities in their own separate regionfiles.

The above list is not complete. The patch documentation will complete it.

New chunk system hard relies on starlight and dataconverter, and most importantly the new concurrent utilities in ConcurrentUtil.

Some of the old async chunk i/o interface (i.e the old file io thread reroutes _some_ calls to the new file io thread) is kept for plugin compat reasons. It will be removed in the next major version of minecraft.

The old legacy chunk system patches have been moved to the removed folder in case we need them again.
2022-09-26 01:02:51 -07:00

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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 15 Jun 2019 08:54:33 -0700
Subject: [PATCH] Fix World#isChunkGenerated calls
Optimize World#loadChunk() too
This patch also adds a chunk status cache on region files (note that
its only purpose is to cache the status on DISK)
diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
index d1af0aca0237ee86acd86fea3255ddeadc3db0d6..06b5fecb37621f66780a396774a37292675d90ac 100644
--- a/src/main/java/net/minecraft/server/level/ChunkMap.java
+++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
@@ -659,9 +659,13 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
// Paper end
private CompletableFuture<Optional<CompoundTag>> readChunk(ChunkPos chunkPos) {
- return this.read(chunkPos).thenApplyAsync((optional) -> {
- return optional.map((nbttagcompound) -> this.upgradeChunkTag(nbttagcompound, chunkPos)); // CraftBukkit
- }, Util.backgroundExecutor());
+ // Paper start - Cache chunk status on disk
+ try {
+ return CompletableFuture.completedFuture(Optional.ofNullable(this.readConvertChunkSync(chunkPos)));
+ } catch (Throwable thr) {
+ return CompletableFuture.failedFuture(thr);
+ }
+ // Paper end - Cache chunk status on disk
}
// CraftBukkit start
@@ -670,6 +674,63 @@ public class ChunkMap extends ChunkStorage implements ChunkHolder.PlayerProvider
// CraftBukkit end
}
+ // Paper start - Cache chunk status on disk
+ @Nullable
+ public CompoundTag readConvertChunkSync(ChunkPos pos) throws IOException {
+ CompoundTag nbttagcompound = this.readSync(pos);
+ // Paper start - Cache chunk status on disk
+ if (nbttagcompound == null) {
+ return null;
+ }
+
+ nbttagcompound = this.upgradeChunkTag(nbttagcompound, pos); // CraftBukkit
+ if (nbttagcompound == null) {
+ return null;
+ }
+
+ this.updateChunkStatusOnDisk(pos, nbttagcompound);
+
+ return nbttagcompound;
+ // Paper end
+ }
+
+ // Paper start - chunk status cache "api"
+ public ChunkStatus getChunkStatusOnDiskIfCached(ChunkPos chunkPos) {
+ net.minecraft.world.level.chunk.storage.RegionFile regionFile = regionFileCache.getRegionFileIfLoaded(chunkPos);
+
+ return regionFile == null ? null : regionFile.getStatusIfCached(chunkPos.x, chunkPos.z);
+ }
+
+ public ChunkStatus getChunkStatusOnDisk(ChunkPos chunkPos) throws IOException {
+ net.minecraft.world.level.chunk.storage.RegionFile regionFile = regionFileCache.getRegionFile(chunkPos, true);
+
+ if (regionFile == null || !regionFileCache.chunkExists(chunkPos)) {
+ return null;
+ }
+
+ ChunkStatus status = regionFile.getStatusIfCached(chunkPos.x, chunkPos.z);
+
+ if (status != null) {
+ return status;
+ }
+
+ this.readChunk(chunkPos);
+
+ return regionFile.getStatusIfCached(chunkPos.x, chunkPos.z);
+ }
+
+ public void updateChunkStatusOnDisk(ChunkPos chunkPos, @Nullable CompoundTag compound) throws IOException {
+ net.minecraft.world.level.chunk.storage.RegionFile regionFile = regionFileCache.getRegionFile(chunkPos, false);
+
+ regionFile.setStatus(chunkPos.x, chunkPos.z, ChunkSerializer.getStatus(compound));
+ }
+
+ public ChunkAccess getUnloadingChunk(int chunkX, int chunkZ) {
+ ChunkHolder chunkHolder = net.minecraft.server.ChunkSystem.getUnloadingChunkHolder(this.level, chunkX, chunkZ);
+ return chunkHolder == null ? null : chunkHolder.getAvailableChunkNow();
+ }
+ // Paper end
+
boolean anyPlayerCloseEnoughForSpawning(ChunkPos pos) {
// Spigot start
return this.anyPlayerCloseEnoughForSpawning(pos, false);
diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFile.java b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFile.java
index 330fb8e6565a5c0490af0c5ca0e7355d81a82e58..861a25a15f1aab20e3245b6d5cdad5d23bdfd6d0 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFile.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFile.java
@@ -51,6 +51,30 @@ public class RegionFile implements AutoCloseable {
public final java.util.concurrent.locks.ReentrantLock fileLock = new java.util.concurrent.locks.ReentrantLock(true); // Paper
public final Path regionFile; // Paper
+ // Paper start - Cache chunk status
+ private final net.minecraft.world.level.chunk.ChunkStatus[] statuses = new net.minecraft.world.level.chunk.ChunkStatus[32 * 32];
+
+ private boolean closed;
+
+ // invoked on write/read
+ public void setStatus(int x, int z, net.minecraft.world.level.chunk.ChunkStatus status) {
+ if (this.closed) {
+ // We've used an invalid region file.
+ throw new IllegalStateException("RegionFile is closed");
+ }
+ this.statuses[getChunkLocation(x, z)] = status;
+ }
+
+ public net.minecraft.world.level.chunk.ChunkStatus getStatusIfCached(int x, int z) {
+ if (this.closed) {
+ // We've used an invalid region file.
+ throw new IllegalStateException("RegionFile is closed");
+ }
+ final int location = getChunkLocation(x, z);
+ return this.statuses[location];
+ }
+ // Paper end
+
public RegionFile(Path file, Path directory, boolean dsync) throws IOException {
this(file, directory, RegionFileVersion.VERSION_DEFLATE, dsync);
}
@@ -398,6 +422,7 @@ public class RegionFile implements AutoCloseable {
return this.getOffset(pos) != 0;
}
+ private static int getChunkLocation(int x, int z) { return (x & 31) + (z & 31) * 32; } // Paper - OBFHELPER - sort of, mirror of logic below
private static int getOffsetIndex(ChunkPos pos) {
return pos.getRegionLocalX() + pos.getRegionLocalZ() * 32;
}
@@ -408,6 +433,7 @@ public class RegionFile implements AutoCloseable {
synchronized (this) {
try {
// Paper end
+ this.closed = true; // Paper
try {
this.padToFullSector();
} finally {
diff --git a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
index 5a25664a15643ff148db47caad4f53376b55168e..7bfb0716964af5ee300150d500c97e8f90c849d4 100644
--- a/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
+++ b/src/main/java/net/minecraft/world/level/chunk/storage/RegionFileStorage.java
@@ -249,6 +249,7 @@ public class RegionFileStorage implements AutoCloseable {
try {
NbtIo.write(nbt, (DataOutput) dataoutputstream);
+ regionfile.setStatus(pos.x, pos.z, ChunkSerializer.getStatus(nbt)); // Paper - cache status on disk
regionfile.setOversized(pos.x, pos.z, false); // Paper - We don't do this anymore, mojang stores differently, but clear old meta flag if it exists to get rid of our own meta file once last oversized is gone
} catch (Throwable throwable) {
if (dataoutputstream != null) {
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index a4fc3e4f13b359e3a33b867e4bd200265e020226..37efb3305b4f740d9092c2a253b93f1925ee75d5 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -299,9 +299,23 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public boolean isChunkGenerated(int x, int z) {
+ // Paper start - Fix this method
+ if (!Bukkit.isPrimaryThread()) {
+ return java.util.concurrent.CompletableFuture.supplyAsync(() -> {
+ return CraftWorld.this.isChunkGenerated(x, z);
+ }, world.getChunkSource().mainThreadProcessor).join();
+ }
+ ChunkAccess chunk = world.getChunkSource().getChunkAtImmediately(x, z);
+ if (chunk == null) {
+ chunk = world.getChunkSource().chunkMap.getUnloadingChunk(x, z);
+ }
+ if (chunk != null) {
+ return chunk instanceof ImposterProtoChunk || chunk instanceof net.minecraft.world.level.chunk.LevelChunk;
+ }
try {
- return this.isChunkLoaded(x, z) || this.world.getChunkSource().chunkMap.read(new ChunkPos(x, z)).get().isPresent();
- } catch (InterruptedException | ExecutionException ex) {
+ return world.getChunkSource().chunkMap.getChunkStatusOnDisk(new ChunkPos(x, z)) == ChunkStatus.FULL;
+ // Paper end
+ } catch (IOException ex) {
throw new RuntimeException(ex);
}
}
@@ -415,20 +429,48 @@ public class CraftWorld extends CraftRegionAccessor implements World {
@Override
public boolean loadChunk(int x, int z, boolean generate) {
org.spigotmc.AsyncCatcher.catchOp("chunk load"); // Spigot
- ChunkAccess chunk = this.world.getChunkSource().getChunk(x, z, generate || isChunkGenerated(x, z) ? ChunkStatus.FULL : ChunkStatus.EMPTY, true); // Paper
+ // Paper start - Optimize this method
+ ChunkPos chunkPos = new ChunkPos(x, z);
- // If generate = false, but the chunk already exists, we will get this back.
- if (chunk instanceof ImposterProtoChunk) {
- // We then cycle through again to get the full chunk immediately, rather than after the ticket addition
- chunk = this.world.getChunkSource().getChunk(x, z, ChunkStatus.FULL, true);
- }
+ if (!generate) {
+ ChunkAccess immediate = world.getChunkSource().getChunkAtImmediately(x, z);
+ if (immediate == null) {
+ immediate = world.getChunkSource().chunkMap.getUnloadingChunk(x, z);
+ }
+ if (immediate != null) {
+ if (!(immediate instanceof ImposterProtoChunk) && !(immediate instanceof net.minecraft.world.level.chunk.LevelChunk)) {
+ return false; // not full status
+ }
+ world.getChunkSource().addRegionTicket(TicketType.PLUGIN, chunkPos, 1, Unit.INSTANCE);
+ world.getChunk(x, z); // make sure we're at ticket level 32 or lower
+ return true;
+ }
- if (chunk instanceof net.minecraft.world.level.chunk.LevelChunk) {
- this.world.getChunkSource().addRegionTicket(TicketType.PLUGIN, new ChunkPos(x, z), 1, Unit.INSTANCE);
- return true;
+ net.minecraft.world.level.chunk.storage.RegionFile file;
+ try {
+ file = world.getChunkSource().chunkMap.regionFileCache.getRegionFile(chunkPos, false);
+ } catch (IOException ex) {
+ throw new RuntimeException(ex);
+ }
+
+ ChunkStatus status = file.getStatusIfCached(x, z);
+ if (!file.hasChunk(chunkPos) || (status != null && status != ChunkStatus.FULL)) {
+ return false;
+ }
+
+ ChunkAccess chunk = world.getChunkSource().getChunk(x, z, ChunkStatus.EMPTY, true);
+ if (!(chunk instanceof ImposterProtoChunk) && !(chunk instanceof net.minecraft.world.level.chunk.LevelChunk)) {
+ return false;
+ }
+
+ // fall through to load
+ // we do this so we do not re-read the chunk data on disk
}
- return false;
+ world.getChunkSource().addRegionTicket(TicketType.PLUGIN, chunkPos, 1, Unit.INSTANCE);
+ world.getChunkSource().getChunk(x, z, ChunkStatus.FULL, true);
+ return true;
+ // Paper end
}
@Override