8274788: Support archived heap objects in ParallelGC

Reviewed-by: iklam, ayang, tschatzl

src/hotspot/share/cds/filemap.cpp

@@ -1994,7 +1994,7 @@ void FileMapInfo::map_or_load_heap_regions() {
     } else if (HeapShared::can_load()) {
       success = HeapShared::load_heap_regions(this);
     } else {
-      log_info(cds)("Cannot use CDS heap data. UseEpsilonGC, UseG1GC or UseSerialGC are required.");
+      log_info(cds)("Cannot use CDS heap data. UseEpsilonGC, UseG1GC, UseSerialGC or UseParallelGC are required.");
     }
   }
 

src/hotspot/share/gc/parallel/parallelScavengeHeap.cpp

@@ -798,6 +798,16 @@ void ParallelScavengeHeap::resize_old_gen(size_t desired_free_space) {
   _old_gen->resize(desired_free_space);
 }
 
+HeapWord* ParallelScavengeHeap::allocate_loaded_archive_space(size_t size) {
+  return _old_gen->allocate(size);
+}
+
+void ParallelScavengeHeap::complete_loaded_archive_space(MemRegion archive_space) {
+  assert(_old_gen->object_space()->used_region().contains(archive_space),
+         "Archive space not contained in old gen");
+  _old_gen->complete_loaded_archive_space(archive_space);
+}
+
 #ifndef PRODUCT
 void ParallelScavengeHeap::record_gen_tops_before_GC() {
   if (ZapUnusedHeapArea) {

src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp

@@ -273,6 +273,11 @@ class ParallelScavengeHeap : public CollectedHeap {
   WorkerThreads& workers() {
     return _workers;
   }
+
+  // Support for loading objects from CDS archive into the heap
+  bool can_load_archived_objects() const { return UseCompressedOops; }
+  HeapWord* allocate_loaded_archive_space(size_t size);
+  void complete_loaded_archive_space(MemRegion archive_space);
 };
 
 // Class that can be used to print information about the

src/hotspot/share/gc/parallel/psOldGen.cpp

@@ -283,6 +283,15 @@ void PSOldGen::shrink(size_t bytes) {
   }
 }
 
+void PSOldGen::complete_loaded_archive_space(MemRegion archive_space) {
+  HeapWord* cur = archive_space.start();
+  while (cur < archive_space.end()) {
+    _start_array.allocate_block(cur);
+    size_t word_size = cast_to_oop(cur)->size();
+    cur += word_size;
+  }
+}
+
 void PSOldGen::resize(size_t desired_free_space) {
   const size_t alignment = virtual_space()->alignment();
   const size_t size_before = virtual_space()->committed_size();

src/hotspot/share/gc/parallel/psOldGen.hpp

@@ -133,6 +133,8 @@ class PSOldGen : public CHeapObj<mtGC> {
     return virtual_space()->uncommitted_size() == 0;
   }
 
+  void complete_loaded_archive_space(MemRegion archive_space);
+
   // Calculating new sizes
   void resize(size_t desired_free_space);
 

test/hotspot/jtreg/TEST.groups

@@ -428,6 +428,7 @@ hotspot_appcds_dynamic = \
  -runtime/cds/appcds/StaticArchiveWithLambda.java \
  -runtime/cds/appcds/TestCombinedCompressedFlags.java \
  -runtime/cds/appcds/TestEpsilonGCWithCDS.java \
+ -runtime/cds/appcds/TestParallelGCWithCDS.java \
  -runtime/cds/appcds/TestSerialGCWithCDS.java \
  -runtime/cds/appcds/TestZGCWithCDS.java \
  -runtime/cds/appcds/UnusedCPDuringDump.java \

test/hotspot/jtreg/runtime/cds/appcds/TestParallelGCWithCDS.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2022, Oracle and/or its affiliates. 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 Loading CDS archived heap objects into ParallelGC
+ * @bug 8274788
+ * @requires vm.cds
+ * @requires vm.gc.Parallel
+ * @requires vm.gc.G1
+ *
+ * @comment don't run this test if any -XX::+Use???GC options are specified, since they will
+ *          interfere with the the test.
+ * @requires vm.gc == null
+ *
+ * @library /test/lib /test/hotspot/jtreg/runtime/cds/appcds
+ * @compile test-classes/Hello.java
+ * @run driver TestParallelGCWithCDS
+ */
+
+import jdk.test.lib.Platform;
+import jdk.test.lib.process.OutputAnalyzer;
+
+public class TestParallelGCWithCDS {
+    public final static String HELLO = "Hello World";
+    static String helloJar;
+
+    public static void main(String... args) throws Exception {
+        helloJar = JarBuilder.build("hello", "Hello");
+
+        // Check if we can use ParallelGC during dump time, or run time, or both.
+        test(false, true);
+        test(true,  false);
+        test(true,  true);
+
+        // With G1 we usually have 2 heap regions. To increase test coverage, we can have 3 heap regions
+        // by using "-Xmx256m -XX:ObjectAlignmentInBytes=64"
+        if (Platform.is64bit()) test(false, true, true);
+    }
+
+    final static String G1 = "-XX:+UseG1GC";
+    final static String Parallel = "-XX:+UseParallelGC";
+
+    static void test(boolean dumpWithParallel, boolean execWithParallel) throws Exception {
+        test(dumpWithParallel, execWithParallel, false);
+    }
+
+    static void test(boolean dumpWithParallel, boolean execWithParallel, boolean useSmallRegions) throws Exception {
+        String dumpGC = dumpWithParallel ? Parallel : G1;
+        String execGC = execWithParallel ? Parallel : G1;
+        String small1 = useSmallRegions ? "-Xmx256m" : "-showversion";
+        String small2 = useSmallRegions ? "-XX:ObjectAlignmentInBytes=64" : "-showversion";
+        OutputAnalyzer out;
+
+        System.out.println("0. Dump with " + dumpGC);
+        out = TestCommon.dump(helloJar,
+                              new String[] {"Hello"},
+                              dumpGC,
+                              small1,
+                              small2,
+                              "-Xlog:cds");
+        out.shouldContain("Dumping shared data to file:");
+        out.shouldHaveExitValue(0);
+
+        System.out.println("1. Exec with " + execGC);
+        out = TestCommon.exec(helloJar,
+                              execGC,
+                              small1,
+                              small2,
+                              "-Xlog:cds",
+                              "Hello");
+        out.shouldContain(HELLO);
+        out.shouldHaveExitValue(0);
+
+        int n = 2;
+        if (!dumpWithParallel && execWithParallel) {
+            // We dumped with G1, so we have an archived heap. At exec time, try to load them into
+            // a small ParallelGC heap that may be too small.
+            String[] sizes = {
+                "4m",   // usually this will success load the archived heap
+                "2m",   // usually this will fail to load the archived heap, but app can launch
+                        // or fail with "GC triggered before VM initialization completed"
+                "1m"    // usually this will cause VM launch to fail with "Too small maximum heap"
+            };
+            for (String sz : sizes) {
+                String xmx = "-Xmx" + sz;
+                System.out.println("=======\n" + n + ". Exec with " + execGC + " " + xmx);
+                out = TestCommon.exec(helloJar,
+                                      execGC,
+                                      small1,
+                                      small2,
+                                      xmx,
+                                      "-Xlog:cds",
+                                      "Hello");
+                if (out.getExitValue() == 0) {
+                    out.shouldContain(HELLO);
+                } else {
+                    String output = out.getStdout() + out.getStderr();
+                    String exp1 = "Too small maximum heap";
+                    String exp2 = "GC triggered before VM initialization completed";
+                    if (!output.contains(exp1) && !output.contains(exp2)) {
+                        throw new RuntimeException("Either '" + exp1 + "' or '" + exp2 + "' must be in stdout/stderr \n");
+                    }
+                }
+                n++;
+            }
+        }
+    }
+}