CompressedClassSpaceSize.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/*
 * @test
 * @bug 8022865
 * @summary Tests for the -XX:CompressedClassSpaceSize command line option
 * @requires vm.bits == 64 & vm.opt.final.UseCompressedOops == true
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 *          java.management
 * @run driver CompressedClassSpaceSize
 */

import jdk.test.lib.process.ProcessTools;
import jdk.test.lib.process.OutputAnalyzer;

public class CompressedClassSpaceSize {

    public static void main(String[] args) throws Exception {
        ProcessBuilder pb;
        OutputAnalyzer output;
        // Minimum size is 1MB
        pb = ProcessTools.createJavaProcessBuilder("-XX:CompressedClassSpaceSize=0",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldContain("outside the allowed range")
              .shouldHaveExitValue(1);

        // Invalid size of -1 should be handled correctly
        pb = ProcessTools.createJavaProcessBuilder("-XX:CompressedClassSpaceSize=-1",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldContain("Improperly specified VM option 'CompressedClassSpaceSize=-1'")
              .shouldHaveExitValue(1);


        // Maximum size is 3GB
        pb = ProcessTools.createJavaProcessBuilder("-XX:CompressedClassSpaceSize=4g",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldContain("outside the allowed range")
              .shouldHaveExitValue(1);


        // Make sure the minimum size is set correctly and printed
        // (Note: ccs size shall be rounded up to the minimum size of 4m since metaspace reservations
        //  are done in a 4m granularity. Note that this is **reserved** size and does not affect rss.
        pb = ProcessTools.createJavaProcessBuilder("-XX:+UnlockDiagnosticVMOptions",
                                                   "-XX:CompressedClassSpaceSize=1m",
                                                   "-Xlog:gc+metaspace=trace",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldMatch("Compressed class space.*4194304")
              .shouldHaveExitValue(0);


        // Make sure the maximum size is set correctly and printed
        pb = ProcessTools.createJavaProcessBuilder("-XX:+UnlockDiagnosticVMOptions",
                                                   "-XX:CompressedClassSpaceSize=3g",
                                                   "-Xlog:gc+metaspace=trace",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldMatch("Compressed class space.*3221225472")
              .shouldHaveExitValue(0);


        pb = ProcessTools.createJavaProcessBuilder("-XX:-UseCompressedClassPointers",
                                                   "-XX:CompressedClassSpaceSize=1m",
                                                   "-version");
        output = new OutputAnalyzer(pb.start());
        output.shouldContain("Setting CompressedClassSpaceSize has no effect when compressed class pointers are not used")
              .shouldHaveExitValue(0);
    }
}