Folia/patches/server/0020-fixup-Rewrite-chunk-system.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sun, 18 Jun 2023 22:56:19 -0700
Subject: [PATCH] fixup! Rewrite chunk system


diff --git a/src/main/java/io/papermc/paper/chunk/system/RegionizedPlayerChunkLoader.java b/src/main/java/io/papermc/paper/chunk/system/RegionizedPlayerChunkLoader.java
index 7b664f32868028758d0c6ee1eaa82efcd83661d2..c5df121d6194a97b20dc390698991b9c72dba538 100644
--- a/src/main/java/io/papermc/paper/chunk/system/RegionizedPlayerChunkLoader.java
+++ b/src/main/java/io/papermc/paper/chunk/system/RegionizedPlayerChunkLoader.java
@@ -788,20 +788,34 @@ public class RegionizedPlayerChunkLoader {
             // try to push more chunk generations
             final long maxGens = Math.max(0L, Math.min(MAX_RATE, Math.min(this.genQueue.size(), this.getMaxChunkGenerates())));
             final int maxGensThisTick = (int)this.chunkGenerateTicketLimiter.takeAllocation(time, genRate, maxGens);
-            for (int i = 0; i < maxGensThisTick; ++i) {
-                final long chunk = this.genQueue.dequeueLong();
-                final byte prev = this.chunkTicketStage.put(chunk, CHUNK_TICKET_STAGE_GENERATING);
+            int ratedGensThisTick = 0;
+            while (!this.genQueue.isEmpty()) {
+                final long chunkKey = this.genQueue.firstLong();
+                final int chunkX = CoordinateUtils.getChunkX(chunkKey);
+                final int chunkZ = CoordinateUtils.getChunkZ(chunkKey);
+                final ChunkAccess chunk = this.world.chunkSource.getChunkAtImmediately(chunkX, chunkZ);
+                if (chunk.getStatus() != ChunkStatus.FULL) {
+                    // only rate limit actual generations
+                    if ((ratedGensThisTick + 1) > maxGensThisTick) {
+                        break;
+                    }
+                    ++ratedGensThisTick;
+                }
+
+                this.genQueue.dequeueLong();
+
+                final byte prev = this.chunkTicketStage.put(chunkKey, CHUNK_TICKET_STAGE_GENERATING);
                 if (prev != CHUNK_TICKET_STAGE_LOADED) {
                     throw new IllegalStateException("Previous state should be " + CHUNK_TICKET_STAGE_LOADED + ", not " + prev);
                 }
                 this.pushDelayedTicketOp(
                     ChunkHolderManager.TicketOperation.addAndRemove(
-                        chunk,
+                        chunkKey,
                         REGION_PLAYER_TICKET, GENERATED_TICKET_LEVEL, this.idBoxed,
                         REGION_PLAYER_TICKET, LOADED_TICKET_LEVEL, this.idBoxed
                     )
                 );
-                this.generatingQueue.enqueue(chunk);
+                this.generatingQueue.enqueue(chunkKey);
             }
 
             // try to pull ticking chunks