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/**
 * @test SpaceUtilizationCheck
 * @summary Check if the space utilization for shared spaces is adequate
 * @requires vm.cds
 * @library /test/lib
 * @build jdk.test.whitebox.WhiteBox
 * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI SpaceUtilizationCheck
 */

import jdk.test.lib.cds.CDSTestUtils;
import jdk.test.lib.cds.CDSOptions;
import jdk.test.lib.process.OutputAnalyzer;
import jdk.test.whitebox.WhiteBox;

import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.util.ArrayList;
import java.util.Hashtable;
import java.lang.Integer;

public class SpaceUtilizationCheck {
    // For the RW/RO regions:
    // [1] Each region must have strictly less than
    //     WhiteBox.metaspaceSharedRegionAlignment() bytes of unused space.
    // [2] There must be no gap between two consecutive regions.

    public static void main(String[] args) throws Exception {
        test("-Xlog:cds=debug");
    }

    static void test(String... extra_options) throws Exception {
        CDSOptions opts = new CDSOptions();
        opts.addSuffix(extra_options);
        OutputAnalyzer output = CDSTestUtils.createArchiveAndCheck(opts);
        Pattern pattern = Pattern.compile("(..) space: *([0-9]+).* out of *([0-9]+) bytes .* at 0x([0-9a0-f]+)");
        WhiteBox wb = WhiteBox.getWhiteBox();
        long reserve_alignment = wb.metaspaceSharedRegionAlignment();
        System.out.println("MetaspaceShared::core_region_alignment() = " + reserve_alignment);

        // Look for output like this. The pattern will only match the first 2 regions, which is what we need to check
        //
        // [0.938s][debug][cds] rw space:   5253952 [ 35.2% of total] out of   5255168 bytes [100.0% used] at 0x0000000800000000
        // [0.938s][debug][cds] ro space:   8353976 [ 55.9% of total] out of   8355840 bytes [100.0% used] at 0x0000000800503000
        // [0.938s][debug][cds] bm space:    262232 [  1.8% of total] out of    262232 bytes [100.0% used]
        // [0.938s][debug][cds] hp space:   1057712 [  7.1% of total] out of   1057712 bytes [100.0% used] at 0x00007fa24c180090
        // [0.938s][debug][cds] total   :  14927872 [100.0% of total] out of  14934960 bytes [100.0% used]

        long last_region = -1;
        Hashtable<String,String> checked = new Hashtable<>();
        for (String line : output.getStdout().split("\n")) {
            if (line.contains(" space:")) {
                Matcher matcher = pattern.matcher(line);
                if (matcher.find()) {
                    String name = matcher.group(1);
                    if (!name.equals("rw") && ! name.equals("ro")) {
                        continue;
                    }
                    System.out.println("Checking " + name + " in : " + line);
                    checked.put(name, name);
                    long used = Long.parseLong(matcher.group(2));
                    long capacity = Long.parseLong(matcher.group(3));
                    long address = Long.parseLong(matcher.group(4), 16);
                    long unused = capacity - used;
                    if (unused < 0) {
                        throw new RuntimeException("Unused space (" + unused + ") less than 0");
                    }
                    if (unused > reserve_alignment) {
                        // [1] Check for unused space
                        throw new RuntimeException("Unused space (" + unused + ") must be smaller than MetaspaceShared::core_region_alignment() (" +
                                                   reserve_alignment + ")");
                    }
                    if (last_region >= 0 && address != last_region) {
                        // [2] Check for no-gap
                        throw new RuntimeException("Region 0x" + address + " should have started at 0x" + Long.toString(last_region, 16));
                    }
                    last_region = address + capacity;
                }
            }
        }
        if (checked.size() != 2) {
          throw new RuntimeException("Must have 2 consecutive, fully utilized regions"); // RW,RO
        }
    }
}