8273508: Support archived heap objects in SerialGC

Reviewed-by: tschatzl, ccheung

src/hotspot/share/cds/filemap.cpp

@@ -1597,8 +1597,9 @@ MapArchiveResult FileMapInfo::map_regions(int regions[], int num_regions, char*
   return MAP_ARCHIVE_SUCCESS;
 }
 
-bool FileMapInfo::read_region(int i, char* base, size_t size) {
+bool FileMapInfo::read_region(int i, char* base, size_t size, bool do_commit) {
   FileMapRegion* si = space_at(i);
+  if (do_commit) {
     log_info(cds)("Commit %s region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT " (%s)%s",
                   is_static() ? "static " : "dynamic", i, p2i(base), p2i(base + size),
                   shared_region_name[i], si->allow_exec() ? " exec" : "");
@@ -1607,6 +1608,7 @@ bool FileMapInfo::read_region(int i, char* base, size_t size) {
                      i, shared_region_name[i]);
       return false;
     }
+  }
   if (lseek(_fd, (long)si->file_offset(), SEEK_SET) != (int)si->file_offset() ||
       read_bytes(base, size) != size) {
     return false;
@@ -1646,7 +1648,7 @@ MapArchiveResult FileMapInfo::map_region(int i, intx addr_delta, char* mapped_ba
     // that covers all the FileMapRegions to ensure all regions can be mapped. However, Windows
     // can't mmap into a ReservedSpace, so we just os::read() the data. We're going to patch all the
     // regions anyway, so there's no benefit for mmap anyway.
-    if (!read_region(i, requested_addr, size)) {
+    if (!read_region(i, requested_addr, size, /* do_commit = */ true)) {
       log_info(cds)("Failed to read %s shared space into reserved space at " INTPTR_FORMAT,
                     shared_region_name[i], p2i(requested_addr));
       return MAP_ARCHIVE_OTHER_FAILURE; // oom or I/O error.
@@ -1817,7 +1819,7 @@ 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. UseG1GC or UseEpsilonGC are required.");
+      log_info(cds)("Cannot use CDS heap data. UseEpsilonGC, UseG1GC or UseSerialGC are required.");
     }
   }
 

src/hotspot/share/cds/filemap.hpp

@@ -477,7 +477,7 @@ public:
                                      int first_region_idx) NOT_CDS_JAVA_HEAP_RETURN;
   bool  has_heap_regions()  NOT_CDS_JAVA_HEAP_RETURN_(false);
   MemRegion get_heap_regions_range_with_current_oop_encoding_mode() NOT_CDS_JAVA_HEAP_RETURN_(MemRegion());
-  bool  read_region(int i, char* base, size_t size);
+  bool  read_region(int i, char* base, size_t size, bool do_commit);
   char* map_bitmap_region();
   void  unmap_region(int i);
   bool  verify_region_checksum(int i);

src/hotspot/share/cds/heapShared.cpp

@@ -1586,7 +1586,7 @@ class PatchLoadedRegionPointers: public BitMapClosure {
 };
 
 int HeapShared::init_loaded_regions(FileMapInfo* mapinfo, LoadedArchiveHeapRegion* loaded_regions,
-                                    uintptr_t* buffer_ret) {
+                                    MemRegion& archive_space) {
   size_t total_bytes = 0;
   int num_loaded_regions = 0;
   for (int i = MetaspaceShared::first_archive_heap_region;
@@ -1604,12 +1604,16 @@ int HeapShared::init_loaded_regions(FileMapInfo* mapinfo, LoadedArchiveHeapRegio
   }
 
   assert(is_aligned(total_bytes, HeapWordSize), "must be");
-  uintptr_t buffer = (uintptr_t)
+  size_t word_size = total_bytes / HeapWordSize;
-    Universe::heap()->allocate_loaded_archive_space(total_bytes / HeapWordSize);
+  HeapWord* buffer = Universe::heap()->allocate_loaded_archive_space(word_size);
-  _loaded_heap_bottom = buffer;
+  if (buffer == nullptr) {
-  _loaded_heap_top    = buffer + total_bytes;
+    return 0;
+  }
+
+  archive_space = MemRegion(buffer, word_size);
+  _loaded_heap_bottom = (uintptr_t)archive_space.start();
+  _loaded_heap_top    = _loaded_heap_bottom + total_bytes;
 
-  *buffer_ret = buffer;
   return num_loaded_regions;
 }
 
@@ -1638,15 +1642,17 @@ bool HeapShared::load_regions(FileMapInfo* mapinfo, LoadedArchiveHeapRegion* loa
     LoadedArchiveHeapRegion* ri = &loaded_regions[i];
     FileMapRegion* r = mapinfo->space_at(ri->_region_index);
 
-    if (!mapinfo->read_region(ri->_region_index, (char*)load_address, r->used())) {
+    if (!mapinfo->read_region(ri->_region_index, (char*)load_address, r->used(), /* do_commit = */ false)) {
       // There's no easy way to free the buffer, so we will fill it with zero later
       // in fill_failed_loaded_region(), and it will eventually be GC'ed.
       log_warning(cds)("Loading of heap region %d has failed. Archived objects are disabled", i);
       _loading_failed = true;
       return false;
     }
-    log_info(cds)("Loaded heap    region #%d at base " INTPTR_FORMAT " size = " SIZE_FORMAT_W(8) " bytes, delta = " INTX_FORMAT,
+    log_info(cds)("Loaded heap    region #%d at base " INTPTR_FORMAT " top " INTPTR_FORMAT
-                  ri->_region_index, load_address, ri->_region_size, ri->_runtime_offset);
+                  " size " SIZE_FORMAT_W(6) " delta " INTX_FORMAT,
+                  ri->_region_index, load_address, load_address + ri->_region_size,
+                  ri->_region_size, ri->_runtime_offset);
 
     uintptr_t oopmap = bitmap_base + r->oopmap_offset();
     BitMapView bm((BitMap::bm_word_t*)oopmap, r->oopmap_size_in_bits());
@@ -1675,10 +1681,14 @@ bool HeapShared::load_heap_regions(FileMapInfo* mapinfo) {
   LoadedArchiveHeapRegion loaded_regions[MetaspaceShared::max_num_heap_regions];
   memset(loaded_regions, 0, sizeof(loaded_regions));
 
-  uintptr_t buffer;
+  MemRegion archive_space;
-  int num_loaded_regions = init_loaded_regions(mapinfo, loaded_regions, &buffer);
+  int num_loaded_regions = init_loaded_regions(mapinfo, loaded_regions, archive_space);
-  sort_loaded_regions(loaded_regions, num_loaded_regions, buffer);
+  if (num_loaded_regions <= 0) {
-  if (!load_regions(mapinfo, loaded_regions, num_loaded_regions, buffer)) {
+    return false;
+  }
+  sort_loaded_regions(loaded_regions, num_loaded_regions, (uintptr_t)archive_space.start());
+  if (!load_regions(mapinfo, loaded_regions, num_loaded_regions, (uintptr_t)archive_space.start())) {
+    assert(_loading_failed, "must be");
     return false;
   }
 
@@ -1711,7 +1721,15 @@ class VerifyLoadedHeapEmbeddedPointers: public BasicOopIterateClosure {
   }
 };
 
-void HeapShared::verify_loaded_heap() {
+void HeapShared::finish_initialization() {
+  if (is_loaded()) {
+    HeapWord* bottom = (HeapWord*)_loaded_heap_bottom;
+    HeapWord* top    = (HeapWord*)_loaded_heap_top;
+
+    MemRegion archive_space = MemRegion(bottom, top);
+    Universe::heap()->complete_loaded_archive_space(archive_space);
+  }
+
   if (VerifyArchivedFields <= 0 || !is_loaded()) {
     return;
   }
@@ -1739,9 +1757,12 @@ void HeapShared::verify_loaded_heap() {
 
 void HeapShared::fill_failed_loaded_region() {
   assert(_loading_failed, "must be");
+  if (_loaded_heap_bottom != 0) {
+    assert(_loaded_heap_top != 0, "must be");
     HeapWord* bottom = (HeapWord*)_loaded_heap_bottom;
     HeapWord* top = (HeapWord*)_loaded_heap_top;
     Universe::heap()->fill_with_objects(bottom, top - bottom);
   }
+}
 
 #endif // INCLUDE_CDS_JAVA_HEAP

src/hotspot/share/cds/heapShared.hpp

@@ -170,7 +170,7 @@ public:
 
   // Can this VM load the objects from archived heap regions into the heap at start-up?
   static bool can_load()  NOT_CDS_JAVA_HEAP_RETURN_(false);
-  static void verify_loaded_heap() NOT_CDS_JAVA_HEAP_RETURN;
+  static void finish_initialization() NOT_CDS_JAVA_HEAP_RETURN;
   static bool is_loaded() {
     CDS_JAVA_HEAP_ONLY(return _is_loaded;)
     NOT_CDS_JAVA_HEAP(return false;)
@@ -346,7 +346,7 @@ private:
   static void init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record);
 
   static int init_loaded_regions(FileMapInfo* mapinfo, LoadedArchiveHeapRegion* loaded_regions,
-                                 uintptr_t* buffer_ret);
+                                 MemRegion& archive_space);
   static void sort_loaded_regions(LoadedArchiveHeapRegion* loaded_regions, int num_loaded_regions,
                                   uintptr_t buffer);
   static bool load_regions(FileMapInfo* mapinfo, LoadedArchiveHeapRegion* loaded_regions,

src/hotspot/share/cds/metaspaceShared.cpp

@@ -1434,7 +1434,7 @@ void MetaspaceShared::initialize_shared_spaces() {
   // Finish up archived heap initialization. These must be
   // done after ReadClosure.
   static_mapinfo->patch_heap_embedded_pointers();
-  HeapShared::verify_loaded_heap();
+  HeapShared::finish_initialization();
 
   // Close the mapinfo file
   static_mapinfo->close();

src/hotspot/share/gc/serial/serialHeap.cpp

@@ -30,6 +30,7 @@
 #include "gc/shared/strongRootsScope.hpp"
 #include "gc/shared/suspendibleThreadSet.hpp"
 #include "memory/universe.hpp"
+#include "runtime/mutexLocker.hpp"
 #include "services/memoryManager.hpp"
 
 SerialHeap* SerialHeap::heap() {
@@ -112,3 +113,13 @@ void SerialHeap::safepoint_synchronize_end() {
     SuspendibleThreadSet::desynchronize();
   }
 }
+
+HeapWord* SerialHeap::allocate_loaded_archive_space(size_t word_size) {
+  MutexLocker ml(Heap_lock);
+  return old_gen()->allocate(word_size, false /* is_tlab */);
+}
+
+void SerialHeap::complete_loaded_archive_space(MemRegion archive_space) {
+  assert(old_gen()->used_region().contains(archive_space), "Archive space not contained in old gen");
+  old_gen()->complete_loaded_archive_space(archive_space);
+}

src/hotspot/share/gc/serial/serialHeap.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 2021, 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
@@ -83,6 +83,11 @@ public:
 
   virtual void safepoint_synchronize_begin();
   virtual void safepoint_synchronize_end();
+
+  // Support for loading objects from CDS archive into the heap
+  bool can_load_archived_objects() const { return true; }
+  HeapWord* allocate_loaded_archive_space(size_t size);
+  void complete_loaded_archive_space(MemRegion archive_space);
 };
 
 #endif // SHARE_GC_SERIAL_SERIALHEAP_HPP

src/hotspot/share/gc/serial/tenuredGeneration.cpp

@@ -219,6 +219,18 @@ void TenuredGeneration::object_iterate(ObjectClosure* blk) {
   _the_space->object_iterate(blk);
 }
 
+void TenuredGeneration::complete_loaded_archive_space(MemRegion archive_space) {
+  // Create the BOT for the archive space.
+  TenuredSpace* space = (TenuredSpace*)_the_space;
+  space->initialize_threshold();
+  HeapWord* start = archive_space.start();
+  while (start < archive_space.end()) {
+    size_t word_size = _the_space->block_size(start);
+    space->alloc_block(start, start + word_size);
+    start += word_size;
+  }
+}
+
 void TenuredGeneration::save_marks() {
   _the_space->set_saved_mark();
 }

src/hotspot/share/gc/serial/tenuredGeneration.hpp

@@ -74,6 +74,8 @@ class TenuredGeneration: public CardGeneration {
   // Iteration
   void object_iterate(ObjectClosure* blk);
 
+  void complete_loaded_archive_space(MemRegion archive_space);
+
   virtual inline HeapWord* allocate(size_t word_size, bool is_tlab);
   virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab);
 

src/hotspot/share/gc/shared/collectedHeap.hpp

@@ -485,6 +485,7 @@ class CollectedHeap : public CHeapObj<mtInternal> {
   // (usually as a snapshot of the old generation).
   virtual bool can_load_archived_objects() const { return false; }
   virtual HeapWord* allocate_loaded_archive_space(size_t size) { return NULL; }
+  virtual void complete_loaded_archive_space(MemRegion archive_space) { }
 
   virtual bool is_oop(oop object) const;
   // Non product verification and debugging.

test/hotspot/jtreg/TEST.groups

@@ -367,8 +367,9 @@ hotspot_appcds_dynamic = \
  -runtime/cds/appcds/SharedArchiveConsistency.java \
  -runtime/cds/appcds/StaticArchiveWithLambda.java \
  -runtime/cds/appcds/TestCombinedCompressedFlags.java \
- -runtime/cds/appcds/TestZGCWithCDS.java \
  -runtime/cds/appcds/TestEpsilonGCWithCDS.java \
+ -runtime/cds/appcds/TestSerialGCWithCDS.java \
+ -runtime/cds/appcds/TestZGCWithCDS.java \
  -runtime/cds/appcds/UnusedCPDuringDump.java \
  -runtime/cds/appcds/VerifierTest_1B.java
 

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

@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2021, 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 SerialGC
+ * @bug 8234679
+ * @requires vm.cds
+ * @requires vm.gc.Serial
+ * @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 TestSerialGCWithCDS
+ */
+
+import jdk.test.lib.Platform;
+import jdk.test.lib.process.OutputAnalyzer;
+
+public class TestSerialGCWithCDS {
+    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 SerialGC during dump time, or run time, or both.
+        test(false, true);
+        test(true,  false);
+        test(true,  true);
+
+        // 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 Serial = "-XX:+UseSerialGC";
+
+    static void test(boolean dumpWithSerial, boolean execWithSerial) throws Exception {
+        test(dumpWithSerial, execWithSerial, false);
+    }
+
+    static void test(boolean dumpWithSerial, boolean execWithSerial, boolean useSmallRegions) throws Exception {
+        String dumpGC = dumpWithSerial ? Serial : G1;
+        String execGC = execWithSerial ? Serial : 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 (dumpWithSerial == false && execWithSerial == true) {
+            // We dumped with G1, so we have an archived heap. At exec time, try to load them into
+            // a small SerialGC heap that may be too small.
+            String[] sizes = {
+                "4m",   // usually this will success load the archived heap
+                "2m",   // usually this will fail to loade th archived heap, but app can launch
+                "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 {
+                    out.shouldContain("Too small maximum heap");
+                }
+                n++;
+            }
+        }
+    }
+}

test/hotspot/jtreg/runtime/cds/appcds/cacheObject/HeapFragmentationTest.java

@@ -28,6 +28,7 @@
  * @bug 8214455
  * @requires vm.cds.write.archived.java.heap
  * @requires (sun.arch.data.model == "64" & os.maxMemory > 4g)
+ * @requires vm.gc == "null"
  * @library /test/lib /test/hotspot/jtreg/runtime/cds/appcds
  * @build HeapFragmentationApp
  * @run driver jdk.test.lib.helpers.ClassFileInstaller -jar HeapFragmentationApp.jar HeapFragmentationApp