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*
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* version 2 for more details (a copy is included in the LICENSE file that
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*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package gc.g1.humongousObjects;
import gc.testlibrary.Helpers;
import jdk.test.lib.Asserts;
import sun.hotspot.WhiteBox;
import java.lang.ref.Reference;
import java.lang.ref.ReferenceQueue;
import java.lang.ref.SoftReference;
import java.lang.ref.WeakReference;
/**
* @test TestObjectCollected
* @summary checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
* actual object behavior
* @requires vm.gc.G1
* @library /test/lib /
* @modules java.base/jdk.internal.misc
* @modules java.management
* @build sun.hotspot.WhiteBox
* @run driver ClassFileInstaller sun.hotspot.WhiteBox
* sun.hotspot.WhiteBox$WhiteBoxPermission
*
* @run main/othervm -XX:+UseG1GC -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions
* -XX:+WhiteBoxAPI -Xbootclasspath/a:. -Xms200m -Xmx200m -Xlog:gc
* -XX:InitiatingHeapOccupancyPercent=100 -XX:G1HeapRegionSize=1M -Xlog:gc=info:file=TestObjectCollected.gc.log
* gc.g1.humongousObjects.TestObjectCollected
*/
/**
* Test checks that after different type of GCs weak/soft references to humongous object behave correspondingly to
* actual object behavior.
* So if object was collected, reference.get() should return null and vice versa
* Since we check humongous objects after such an object is collected the region where it was allocated becomes free
* or/and change type to non-humongous. Two WhiteBox method were used - first returns if a region containing certain
* address is free and second - if a region containing certain address is humongous
*/
public class TestObjectCollected {
/**
* Provides methods to initiate GC of requested type
*/
private enum GC {
YOUNG_CG {
@Override
public void provoke() {
WHITE_BOX.youngGC();
}
},
FULL_GC {
@Override
public void provoke() {
System.gc();
}
},
CMC {
@Override
public void provoke() {
Helpers.waitTillCMCFinished(WHITE_BOX, 0);
WHITE_BOX.g1StartConcMarkCycle();
Helpers.waitTillCMCFinished(WHITE_BOX, 0);
}
},
FULL_GC_MEMORY_PRESSURE {
@Override
public void provoke() {
WHITE_BOX.fullGC();
}
};
private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
public abstract void provoke();
}
/**
* Factory for weak and soft references.
* Allocates byte array of ALLOCATION_SIZE and returns weak/soft reference on it.
*/
private enum REF_FACTORY {
WEAK {
@Override
public Reference<byte[]> create() {
return new WeakReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
}
},
SOFT {
@Override
public Reference<byte[]> create() {
return new SoftReference<>(new byte[ALLOCATION_SIZE], referenceQueqe);
}
};
private static final ReferenceQueue<byte[]> referenceQueqe = new ReferenceQueue<>();
private static final int ALLOCATION_SIZE = WhiteBox.getWhiteBox().g1RegionSize() * 2 / 3;
/**
* Factory method
*
* @return weak/soft reference on byte array of ALLOCATION_SIZE
*/
public abstract Reference<byte[]> create();
}
private static final WhiteBox WHITE_BOX = WhiteBox.getWhiteBox();
/**
* Does actual testing:
* Gets a reference
* Gets address of referenced object using WB method
* Calls gc of provided type
* Checks that object was/was not deleted using WB methods.
*/
public static void doTesting(GC gc, REF_FACTORY ref) {
System.out.println(String.format("Testing %s reference behavior after %s", ref.name(), gc.name()));
Reference reference = ref.create();
Asserts.assertNotNull(reference, "Test Bug: failed to allocate reference");
long adr = WHITE_BOX.getObjectAddress(reference.get());
//Sanity checks
boolean isRefNulled = (reference.get() == null);
boolean isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
boolean isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
Asserts.assertEquals(isRefNulled, false,
"We just allocated an object but reference.get() already returned null");
Asserts.assertEquals(isRegionFree, false,
"We just allocated an object but WB returns that allocation region is still considered free");
Asserts.assertEquals(isRegionHumongous, true,
"We just allocated a humongous object but WB returns that allocation region is not humongous");
gc.provoke();
isRefNulled = (reference.get() == null);
isRegionHumongous = WHITE_BOX.g1BelongsToHumongousRegion(adr);
isRegionFree = WHITE_BOX.g1BelongsToFreeRegion(adr);
boolean isObjCollected = isRegionFree || !isRegionHumongous;
Asserts.assertEquals(isRefNulled, isObjCollected,
String.format("There is an inconsistensy between reference and white box "
+ "method behavior - one considers object referenced with "
+ "%s type collected and another doesn't!\n"
+ "\treference.get() returned %snull\n"
+ "\tWhiteBox methods returned that object was%s collected",
reference.getClass().getSimpleName(),
(isRefNulled ? "" : "not "),
(isObjCollected ? "" : " not")));
System.out.println("Passed");
}
/**
* Entry point
*
* @param args not used
*/
public static void main(String[] args) {
// Full gc - System.gc()
TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.WEAK);
TestObjectCollected.doTesting(GC.FULL_GC, REF_FACTORY.SOFT);
// Full gc with memory pressure - WB.fullGC() emulates that no memory left
TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.WEAK);
TestObjectCollected.doTesting(GC.FULL_GC_MEMORY_PRESSURE, REF_FACTORY.SOFT);
// Young gc
TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.WEAK);
TestObjectCollected.doTesting(GC.YOUNG_CG, REF_FACTORY.SOFT);
// Concurrent mark cycle
TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.WEAK);
TestObjectCollected.doTesting(GC.CMC, REF_FACTORY.SOFT);
}
}