Fixed container memory pressure

- Container pressure excludes committed heap the JVM is not using
- Reclaim, pregen gating and status text use the adjusted figure
- Tests cover the committed heap subtraction

core/src/main/java/art/arcane/iris/world/pregen/MantleHeapPressure.java

@@ -65,7 +65,8 @@ public final class MantleHeapPressure {
     }
 
     public static double usedFraction() {
-        return pressureFraction(heapUsedFraction(), ContainerMemory.snapshot().pressureFraction());
+        MemoryUsage heap = heapUsage();
+        return pressureFraction(heapUsedFraction(heap), containerPressureFraction(ContainerMemory.snapshot(), heap));
     }
 
     public static long memoryBudgetBytes() {
@@ -76,6 +77,14 @@ public final class MantleHeapPressure {
         return Math.min(heapBytes, containerBytes - containerBytes / 4L);
     }
 
+    static double containerPressureFraction(ContainerMemory.Snapshot container, long heapCommittedBytes, long heapUsedBytes) {
+        if (!container.supported()) {
+            return 0D;
+        }
+        long freeCommittedHeap = Math.max(0L, heapCommittedBytes - heapUsedBytes);
+        return Math.max(0D, container.pressureFraction() - (double) freeCommittedHeap / (double) container.limitBytes());
+    }
+
     static double pressureFraction(double heapFraction, double containerFraction) {
         if (containerFraction >= CONTAINER_HIGH_WATER) {
             return Math.max(heapFraction, HIGH_WATER + (containerFraction - CONTAINER_HIGH_WATER));
@@ -88,14 +97,22 @@ public final class MantleHeapPressure {
 
     public static String describe() {
         ContainerMemory.Snapshot container = ContainerMemory.snapshot();
-        String heap = Math.round(heapUsedFraction() * 100D) + "% heap";
+        MemoryUsage heapUsage = heapUsage();
+        String heap = Math.round(heapUsedFraction(heapUsage) * 100D) + "% heap";
         return container.supported()
-                ? heap + ", " + Math.round(container.pressureFraction() * 100D) + "% container working memory"
+                ? heap + ", " + Math.round(containerPressureFraction(container, heapUsage) * 100D) + "% container working memory"
                 : heap;
     }
 
-    private static double heapUsedFraction() {
-        MemoryUsage heap = ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
+    private static MemoryUsage heapUsage() {
+        return ManagementFactory.getMemoryMXBean().getHeapMemoryUsage();
+    }
+
+    private static double containerPressureFraction(ContainerMemory.Snapshot container, MemoryUsage heap) {
+        return containerPressureFraction(container, heap.getCommitted(), heap.getUsed());
+    }
+
+    private static double heapUsedFraction(MemoryUsage heap) {
         long max = heap.getMax();
         if (max <= 0L) {
             Runtime runtime = Runtime.getRuntime();
@@ -110,8 +127,9 @@ public final class MantleHeapPressure {
     }
 
     public static boolean overHighWater() {
-        boolean heapPressure = PRESSURE_GATE.update(heapUsedFraction());
-        boolean containerPressure = CONTAINER_PRESSURE_GATE.update(ContainerMemory.snapshot().pressureFraction());
+        MemoryUsage heap = heapUsage();
+        boolean heapPressure = PRESSURE_GATE.update(heapUsedFraction(heap));
+        boolean containerPressure = CONTAINER_PRESSURE_GATE.update(containerPressureFraction(ContainerMemory.snapshot(), heap));
         return heapPressure || containerPressure;
     }
 

core/src/test/java/art/arcane/iris/world/pregen/MantleContainerPressureTest.java

@@ -1,5 +1,6 @@
 package art.arcane.iris.world.pregen;
 
+import art.arcane.volmlib.util.diagnostics.ContainerMemory;
 import org.junit.Test;
 
 import java.util.concurrent.atomic.AtomicLong;
@@ -9,6 +10,8 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 public class MantleContainerPressureTest {
+    private static final long MIB = 1L << 20;
+
     @Test
     public void containerPressureReclaimsEvenWhenTheHeapHasHeadroom() {
         double pressure = MantleHeapPressure.pressureFraction(0.45D, 0.90D);
@@ -39,4 +42,37 @@ public class MantleContainerPressureTest {
         assertTrue(gate.update(0.85D));
         assertFalse(gate.update(0.80D));
     }
+
+    @Test
+    public void freeCommittedHeapDoesNotCountAsContainerPressure() {
+        ContainerMemory.Snapshot container = containerAt(8_601L * MIB, 8_240L * MIB);
+        double containerPressure = MantleHeapPressure.containerPressureFraction(container, 7_388L * MIB, 2_355L * MIB);
+        assertEquals((8_240D - 5_033D) / 8_601D, containerPressure, 1E-9D);
+        assertEquals(0D, MantleHeapPressure.reclaimUrgency(MantleHeapPressure.pressureFraction(0.31D, containerPressure)), 0D);
+    }
+
+    @Test
+    public void heapFillingItsCommittedSpaceStillRaisesContainerPressure() {
+        ContainerMemory.Snapshot container = containerAt(8_601L * MIB, 8_240L * MIB);
+        double containerPressure = MantleHeapPressure.containerPressureFraction(container, 7_388L * MIB, 7_200L * MIB);
+        assertTrue(containerPressure >= 0.90D);
+        assertEquals(1D, MantleHeapPressure.reclaimUrgency(MantleHeapPressure.pressureFraction(0.94D, containerPressure)), 0D);
+    }
+
+    @Test
+    public void containerPressureNeverDropsBelowZero() {
+        ContainerMemory.Snapshot container = containerAt(4_096L * MIB, 1_024L * MIB);
+        assertEquals(0D, MantleHeapPressure.containerPressureFraction(container, 3_072L * MIB, 512L * MIB), 0D);
+    }
+
+    @Test
+    public void unlimitedContainersReportNoContainerPressure() {
+        ContainerMemory.Snapshot container = new ContainerMemory.Snapshot(Long.MAX_VALUE, 0L, 0L, 0D, Long.MAX_VALUE);
+        assertEquals(0D, MantleHeapPressure.containerPressureFraction(container, 7_388L * MIB, 2_355L * MIB), 0D);
+    }
+
+    private static ContainerMemory.Snapshot containerAt(long limitBytes, long workingSetBytes) {
+        return new ContainerMemory.Snapshot(limitBytes, workingSetBytes, workingSetBytes,
+                workingSetBytes / (double) limitBytes, limitBytes - workingSetBytes);
+    }
 }