SapMachine #1670: jcmd GC.heap_dump without options should write to l…

…ocation given by -XX:HeapDumpPath, if set

src/hotspot/share/runtime/globals.hpp

@@ -693,10 +693,12 @@ const int ObjectAlignmentInBytes = 8;
           "Dump heap to file when java.lang.OutOfMemoryError is thrown "    \
           "from JVM")                                                       \
                                                                             \
+  /* SapMachine 2024-05-10: HeapDumpPath for jcmd */                        \
   product(ccstr, HeapDumpPath, nullptr, MANAGEABLE,                         \
-          "When HeapDumpOnOutOfMemoryError is on, the path (filename or "   \
-          "directory) of the dump file (defaults to java_pid<pid>.hprof "   \
-          "in the working directory)")                                      \
+          "When HeapDumpOnOutOfMemoryError is on, or a heap dump is "       \
+          "triggered by jcmd GC.heap_dump without specifying a path, "      \
+          "the path (filename or directory) of the dump file. "             \
+          "(defaults to java_pid<pid>.hprof in the working directory)")     \
                                                                             \
   product(intx, HeapDumpGzipLevel, 0, MANAGEABLE,                           \
           "When HeapDumpOnOutOfMemoryError is on, the gzip compression "    \

src/hotspot/share/services/diagnosticCommand.cpp

@@ -483,7 +483,8 @@ void FinalizerInfoDCmd::execute(DCmdSource source, TRAPS) {
 #if INCLUDE_SERVICES // Heap dumping/inspection supported
 HeapDumpDCmd::HeapDumpDCmd(outputStream* output, bool heap) :
                            DCmdWithParser(output, heap),
-  _filename("filename","Name of the dump file", "STRING",true),
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  _filename("filename", "Name of the dump file", "STRING", false, "if no filename was specified, but -XX:HeapDumpPath=<hdp> is set, path <hdp> is taken"),
   _all("-all", "Dump all objects, including unreachable objects",
        "BOOLEAN", false, "false"),
   _gzip("-gz", "If specified, the heap dump is written in gzipped format "
@@ -499,6 +500,8 @@ HeapDumpDCmd::HeapDumpDCmd(outputStream* output, bool heap) :
 
 void HeapDumpDCmd::execute(DCmdSource source, TRAPS) {
   jlong level = -1; // -1 means no compression.
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  bool use_heapdump_path = false;
 
   if (_gzip.is_set()) {
     level = _gzip.value();
@@ -509,11 +512,27 @@ void HeapDumpDCmd::execute(DCmdSource source, TRAPS) {
     }
   }
 
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  if (!_filename.is_set()) {
+    if (HeapDumpPath != nullptr) {
+      // use HeapDumpPath (file or directory is possible)
+      use_heapdump_path = true;
+    } else {
+      output()->print_cr("Filename or -XX:HeapDumpPath must be set!");
+      return;
+    }
+  }
+
   // Request a full GC before heap dump if _all is false
   // This helps reduces the amount of unreachable objects in the dump
   // and makes it easier to browse.
-  HeapDumper dumper(!_all.value() /* request GC if _all is false*/);
-  dumper.dump(_filename.value(), output(), (int) level, _overwrite.value());
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  if (use_heapdump_path) {
+    HeapDumper::dump_heap(!_all.value(), output(), (int) level, _overwrite.value());
+  } else {
+    HeapDumper dumper(!_all.value() /* request GC if _all is false*/);
+    dumper.dump(_filename.value(), output(), (int) level, _overwrite.value());
+  }
 }
 
 ClassHistogramDCmd::ClassHistogramDCmd(outputStream* output, bool heap) :

src/hotspot/share/services/heapDumper.cpp

@@ -2605,7 +2605,8 @@ void HeapDumper::set_error(char const* error) {
 // Called by out-of-memory error reporting by a single Java thread
 // outside of a JVM safepoint
 void HeapDumper::dump_heap_from_oome() {
-  HeapDumper::dump_heap(true);
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  HeapDumper::dump_heap(false, true);
 }
 
 // Called by error reporting by a single Java thread outside of a JVM safepoint,
@@ -2614,17 +2615,26 @@ void HeapDumper::dump_heap_from_oome() {
 // general use, however, this method will need modification to prevent
 // inteference when updating the static variables base_path and dump_file_seq below.
 void HeapDumper::dump_heap() {
-  HeapDumper::dump_heap(false);
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  HeapDumper::dump_heap(false, false);
 }
 
-void HeapDumper::dump_heap(bool oome) {
+// SapMachine 2024-05-10: HeapDumpPath for jcmd
+void HeapDumper::dump_heap(bool gc_before_heap_dump, outputStream* out, int compression, bool overwrite) {
+  HeapDumper::dump_heap(gc_before_heap_dump, false, out, compression, overwrite);
+}
+
+// SapMachine 2024-05-10: HeapDumpPath for jcmd
+void HeapDumper::dump_heap(bool gc_before_heap_dump, bool oome, outputStream* out, int compression, bool overwrite) {
   static char base_path[JVM_MAXPATHLEN] = {'\0'};
   static uint dump_file_seq = 0;
   char* my_path;
   const int max_digit_chars = 20;
 
   const char* dump_file_name = "java_pid";
-  const char* dump_file_ext  = HeapDumpGzipLevel > 0 ? ".hprof.gz" : ".hprof";
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  const int ziplevel = compression < 0 ? HeapDumpGzipLevel : compression;
+  const char* dump_file_ext  = ziplevel > 0 ? ".hprof.gz" : ".hprof";
 
   // The dump file defaults to java_pid<pid>.hprof in the current working
   // directory. HeapDumpPath=<file> can be used to specify an alternative
@@ -2689,8 +2699,10 @@ void HeapDumper::dump_heap(bool oome) {
   }
   dump_file_seq++;   // increment seq number for next time we dump
 
-  HeapDumper dumper(false /* no GC before heap dump */,
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  HeapDumper dumper(gc_before_heap_dump /* GC before heap dump */,
                     oome  /* pass along out-of-memory-error flag */);
-  dumper.dump(my_path, tty, HeapDumpGzipLevel);
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  dumper.dump(my_path, out, ziplevel, overwrite);
   os::free(my_path);
 }

src/hotspot/share/services/heapDumper.hpp

@@ -60,7 +60,8 @@ class HeapDumper : public StackObj {
   // internal timer.
   elapsedTimer* timer()                 { return &_t; }
 
-  static void dump_heap(bool oome);
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  static void dump_heap(bool gc_before_heap_dump, bool oome, outputStream* out = tty, int compression = -1, bool overwrite = false);
 
  public:
   HeapDumper(bool gc_before_heap_dump) :
@@ -80,6 +81,10 @@ class HeapDumper : public StackObj {
   static void dump_heap()    NOT_SERVICES_RETURN;
 
   static void dump_heap_from_oome()    NOT_SERVICES_RETURN;
+
+  // SapMachine 2024-05-10: HeapDumpPath for jcmd
+  static void dump_heap(bool gc_before_heap_dump, outputStream* out, int compression, bool overwrite)    NOT_SERVICES_RETURN;
+
 };
 
 #endif // SHARE_SERVICES_HEAPDUMPER_HPP

test/hotspot/jtreg/serviceability/HeapDump/HeapDumpJcmdPresetPathTest.java

@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2024 SAP SE. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @summary Test jcmd GC.heap_dump without path option; path is set via HeapDumpPath
+ * @library /test/lib
+ * @run main/othervm -XX:HeapDumpPath=testjcmd.hprof HeapDumpJcmdPresetPathTest
+ */
+
+import java.io.File;
+
+import jdk.test.lib.Asserts;
+import jdk.test.lib.dcmd.PidJcmdExecutor;
+import jdk.test.lib.process.OutputAnalyzer;
+
+public class HeapDumpJcmdPresetPathTest {
+
+    public static void main(String[] args) throws Exception {
+        PidJcmdExecutor executor = new PidJcmdExecutor();
+        OutputAnalyzer output = executor.execute("GC.heap_dump");
+        output.shouldContain("Dumping heap to testjcmd.hprof");
+        output.shouldContain("Heap dump file created");
+
+        Asserts.assertTrue(new File("testjcmd.hprof").exists());
+    }
+}