attempted to improve ingest perfomance by only saving on section unload

src/main/java/me/cortex/voxy/common/world/ActiveSectionTracker.java

@@ -190,6 +190,23 @@ public class ActiveSectionTracker {
 
     void tryUnload(WorldSection section) {
         if (this.engine != null) this.engine.lastActiveTime = System.currentTimeMillis();
+        if (section.isDirty&&this.engine!=null) {
+            if (section.tryAcquire()) {
+                if (section.setNotDirty()) {//If the section is dirty we must enqueue for saving
+                    this.engine.saveSection(section);
+                }
+                section.release(false);//Special
+            } else {
+                VarHandle.loadLoadFence();
+                if (section.isDirty) {
+                    throw new IllegalStateException("Section was dirty but is also unloaded, this is very bad");
+                }
+            }
+        }
+
+        if (section.getRefCount() != 0) {
+            return;
+        }
         int index = this.getCacheArrayIndex(section.key);
         final var cache = this.loadedSectionCache[index];
         WorldSection sec = null;

src/main/java/me/cortex/voxy/common/world/WorldEngine.java

@@ -118,8 +118,8 @@ public class WorldEngine {
         if (this.dirtyCallback != null) {
             this.dirtyCallback.accept(section, changeState);
         }
-        if (this.saveCallback != null) {
-            this.saveCallback.save(this, section);
+        if (!section.inSaveQueue) {
+            section.markDirty();
         }
     }
 
@@ -181,4 +181,11 @@ public class WorldEngine {
         //TODO: maybe dont need to tick the last active time?
         this.lastActiveTime = System.currentTimeMillis();
     }
+
+    public void saveSection(WorldSection section) {
+        section.setNotDirty();
+        if (this.saveCallback != null) {
+            this.saveCallback.save(this, section);
+        }
+    }
 }

src/main/java/me/cortex/voxy/common/world/WorldSection.java

@@ -22,12 +22,16 @@ public final class WorldSection {
     static final VarHandle ATOMIC_STATE_HANDLE;
     private static final VarHandle NON_EMPTY_CHILD_HANDLE;
     private static final VarHandle NON_EMPTY_BLOCK_HANDLE;
+    private static final VarHandle IN_SAVE_QUEUE_HANDLE;
+    private static final VarHandle IS_DIRTY_HANDLE;
 
     static {
         try {
             ATOMIC_STATE_HANDLE = MethodHandles.lookup().findVarHandle(WorldSection.class, "atomicState", int.class);
             NON_EMPTY_CHILD_HANDLE = MethodHandles.lookup().findVarHandle(WorldSection.class, "nonEmptyChildren", byte.class);
             NON_EMPTY_BLOCK_HANDLE = MethodHandles.lookup().findVarHandle(WorldSection.class, "nonEmptyBlockCount", int.class);
+            IN_SAVE_QUEUE_HANDLE = MethodHandles.lookup().findVarHandle(WorldSection.class, "inSaveQueue", boolean.class);
+            IS_DIRTY_HANDLE = MethodHandles.lookup().findVarHandle(WorldSection.class, "isDirty", boolean.class);
         } catch (NoSuchFieldException | IllegalAccessException e) {
             throw new RuntimeException(e);
         }
@@ -55,7 +59,8 @@ public final class WorldSection {
     volatile byte nonEmptyChildren;
 
     final ActiveSectionTracker tracker;
-    public final AtomicBoolean inSaveQueue = new AtomicBoolean();
+    volatile boolean inSaveQueue;
+    volatile boolean isDirty;
 
     //When the first bit is set it means its loaded
     @SuppressWarnings("all")
@@ -131,6 +136,10 @@ public final class WorldSection {
 
     //TODO: add the ability to hint to the tracker that yes the section is unloaded, try to cache it in a secondary cache since it will be reused/needed later
     public int release() {
+        return release(true);
+    }
+
+    int release(boolean unload) {
         int state = ((int) ATOMIC_STATE_HANDLE.getAndAdd(this, -2)) - 2;
         if (state < 1) {
             throw new IllegalStateException("Section got into an invalid state");
@@ -138,7 +147,7 @@ public final class WorldSection {
         if ((state & 1) == 0) {
             throw new IllegalStateException("Tried releasing a freed section");
         }
-        if ((state>>1)==0) {
+        if ((state>>1)==0 && unload) {
             if (this.tracker != null) {
                 this.tracker.tryUnload(this);
             } else {
@@ -271,4 +280,20 @@ public final class WorldSection {
     public static WorldSection _createRawUntrackedUnsafeSection(int lvl, int x, int y, int z) {
         return new WorldSection(lvl, x, y, z, null);
     }
+
+    public boolean exchangeIsInSaveQueue(boolean state) {
+        return ((boolean) IN_SAVE_QUEUE_HANDLE.compareAndExchange(this, !state, state)) == !state;
+    }
+
+    public void markDirty() {
+        IS_DIRTY_HANDLE.getAndSet(this, true);
+    }
+
+    public boolean setNotDirty() {
+        return (boolean) IS_DIRTY_HANDLE.getAndSet(this, false);
+    }
+
+    public boolean isFreed() {
+        return (((int)ATOMIC_STATE_HANDLE.get(this))&1)==0;
+    }
 }

src/main/java/me/cortex/voxy/common/world/service/SectionSavingService.java

@@ -28,8 +28,9 @@ public class SectionSavingService {
         var section = task.section;
         section.assertNotFree();
         try {
-            section.inSaveQueue.set(false);
-            task.engine.storage.saveSection(section);
+            if (section.exchangeIsInSaveQueue(false)) {
+                task.engine.storage.saveSection(section);
+            }
         } catch (Exception e) {
             Logger.error("Voxy saver had an exception while executing please check logs and report error", e);
         }
@@ -47,7 +48,7 @@ public class SectionSavingService {
 
     public void enqueueSave(WorldEngine in, WorldSection section) {
         //If its not enqueued for saving then enqueue it
-        if (!section.inSaveQueue.getAndSet(true)) {
+        if (section.exchangeIsInSaveQueue(true)) {
             //Acquire the section for use
             section.acquire();