8256450: Add gz option to jmap to write a gzipped heap dump

Reviewed-by: cjplummer, sspitsyn, phh

src/hotspot/share/services/attachListener.cpp

@@ -218,6 +218,7 @@ static jint jcmd(AttachOperation* op, outputStream* out) {
 // Input arguments :-
 //   arg0: Name of the dump file
 //   arg1: "-live" or "-all"
+//   arg2: Compress level
 jint dump_heap(AttachOperation* op, outputStream* out) {
   const char* path = op->arg(0);
   if (path == NULL || path[0] == '\0') {
@@ -233,11 +234,22 @@ jint dump_heap(AttachOperation* op, outputStream* out) {
       live_objects_only = strcmp(arg1, "-live") == 0;
     }
 
+    const char* num_str = op->arg(2);
+    uintx level = 0;
+    if (num_str != NULL && num_str[0] != '\0') {
+      if (!Arguments::parse_uintx(num_str, &level, 0)) {
+        out->print_cr("Invalid compress level: [%s]", num_str);
+        return JNI_ERR;
+      } else if (level < 1 || level > 9) {
+        out->print_cr("Compression level out of range (1-9): " UINTX_FORMAT, level);
+        return JNI_ERR;
+      }
+    }
     // Request a full GC before heap dump if live_objects_only = true
     // This helps reduces the amount of unreachable objects in the dump
     // and makes it easier to browse.
     HeapDumper dumper(live_objects_only /* request GC */);
-    dumper.dump(op->arg(0), out);
+    dumper.dump(op->arg(0), out, (int)level);
   }
   return JNI_OK;
 }

src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java

@@ -209,6 +209,7 @@ public class JMap {
         String subopts[] = options.split(",");
         String filename = null;
         String liveopt = "-all";
+        String compress_level = null;
 
         for (int i = 0; i < subopts.length; i++) {
             String subopt = subopts[i];
@@ -224,6 +225,12 @@ public class JMap {
                 }
             } else if (subopt.equals("format=b")) {
                 // ignore format (not needed at this time)
+            } else if (subopt.startsWith("gz=")) {
+               compress_level = subopt.substring("gz=".length());
+               if (compress_level == null) {
+                    System.err.println("Fail: no number provided in option: '" + subopt + "'");
+                    usage(1);
+               }
             } else {
                 System.err.println("Fail: invalid option: '" + subopt + "'");
                 usage(1);
@@ -238,7 +245,7 @@ public class JMap {
         System.out.flush();
 
         // dumpHeap is not the same as jcmd GC.heap_dump
-        executeCommandForPid(pid, "dumpheap", filename, liveopt);
+        executeCommandForPid(pid, "dumpheap", filename, liveopt, compress_level);
     }
 
     private static void checkForUnsupportedOptions(String[] args) {
@@ -303,6 +310,8 @@ public class JMap {
         System.err.println("      all          dump all objects in the heap (default if one of \"live\" or \"all\" is not specified)");
         System.err.println("      format=b     binary format");
         System.err.println("      file=<file>  dump heap to <file>");
+        System.err.println("      gz=<number>  If specified, the heap dump is written in gzipped format using the given compression level.");
+        System.err.println("                   1 (recommended) is the fastest, 9 the strongest compression.");
         System.err.println("");
         System.err.println("    Example: jmap -dump:live,format=b,file=heap.bin <pid>");
         System.err.println("");

test/jdk/sun/tools/jmap/BasicJMapTest.java

@@ -22,10 +22,13 @@
  */
 
 import static jdk.test.lib.Asserts.assertTrue;
+import static jdk.test.lib.Asserts.assertFalse;
 import static jdk.test.lib.Asserts.fail;
 
 import java.io.File;
+import java.nio.file.Files;
 import java.util.Arrays;
+import java.util.List;
 
 import jdk.test.lib.JDKToolLauncher;
 import jdk.test.lib.Utils;
@@ -114,6 +117,7 @@ public class BasicJMapTest {
         testDump();
         testDumpLive();
         testDumpAll();
+        testDumpCompressed();
     }
 
     private static void testHisto() throws Exception {
@@ -211,20 +215,25 @@ public class BasicJMapTest {
     }
 
     private static void testDump() throws Exception {
-        dump(false, false);
+        dump(false, false, false);
     }
 
     private static void testDumpLive() throws Exception {
-        dump(true, false);
+        dump(true, false, false);
     }
 
     private static void testDumpAll() throws Exception {
-        dump(false, true);
+        dump(false, true, false);
     }
 
-    private static void dump(boolean live, boolean explicitAll) throws Exception {
+    private static void testDumpCompressed() throws Exception {
+        dump(true, false, true);
+    }
+
+    private static void dump(boolean live, boolean explicitAll, boolean compressed) throws Exception {
         String liveArg = "";
         String fileArg = "";
+        String compressArg = "";
         String allArgs = "-dump:";
 
         if (live && explicitAll) {
@@ -237,14 +246,20 @@ public class BasicJMapTest {
             liveArg = "all,";
         }
 
-        File file = new File("jmap.dump" + System.currentTimeMillis() + ".hprof");
+        String filePath = "jmap.dump" + System.currentTimeMillis() + ".hprof";
+        if (compressed) {
+            compressArg = "gz=1,";
+            filePath = filePath + ".gz";
+        }
+
+        File file = new File(filePath);
         if (file.exists()) {
             file.delete();
         }
         fileArg = "file=" + file.getName();
 
         OutputAnalyzer output;
-        allArgs = allArgs + liveArg + "format=b," + fileArg;
+        allArgs = allArgs + liveArg + compressArg + "format=b," + fileArg;
         output = jmap(allArgs);
         output.shouldHaveExitValue(0);
         output.shouldContain("Heap dump file created");
@@ -255,7 +270,18 @@ public class BasicJMapTest {
     private static void verifyDumpFile(File dump) {
         assertTrue(dump.exists() && dump.isFile(), "Could not create dump file " + dump.getAbsolutePath());
         try {
-            HprofParser.parse(dump);
+            File out = HprofParser.parse(dump);
+
+            assertTrue(out != null && out.exists() && out.isFile(),
+                       "Could not find hprof parser output file");
+            List<String> lines = Files.readAllLines(out.toPath());
+            assertTrue(lines.size() > 0, "hprof parser output file is empty");
+            for (String line : lines) {
+                assertFalse(line.matches(".*WARNING(?!.*Failed to resolve " +
+                                         "object.*constantPoolOop.*).*"));
+            }
+
+            out.delete();
         } catch (Exception e) {
             e.printStackTrace();
             fail("Could not parse dump file " + dump.getAbsolutePath());