--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/memory/compactingPermGenGen.cpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,457 @@
+/*
+ * Copyright 2003-2006 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_compactingPermGenGen.cpp.incl"
+
+
+// Recursively adjust all pointers in an object and all objects by
+// referenced it.  Clear marks on objects in order to prevent visiting
+// any object twice.
+
+class RecursiveAdjustSharedObjectClosure : public OopClosure {
+public:
+  void do_oop(oop* o) {
+    oop obj = *o;
+    if (obj->is_shared_readwrite()) {
+      if (obj->mark()->is_marked()) {
+        obj->init_mark();         // Don't revisit this object.
+        obj->oop_iterate(this);   // Recurse - adjust objects referenced.
+        obj->adjust_pointers();   // Adjust this object's references.
+
+        // Special case: if a class has a read-only constant pool,
+        // then the read-write objects referenced by the pool must
+        // have their marks reset.
+
+        if (obj->klass() == Universe::instanceKlassKlassObj()) {
+          instanceKlass* ik = instanceKlass::cast((klassOop)obj);
+          constantPoolOop cp = ik->constants();
+          if (cp->is_shared_readonly()) {
+            cp->oop_iterate(this);
+          }
+        }
+      }
+    }
+  };
+};
+
+
+// We need to go through all placeholders in the system dictionary and
+// try to resolve them into shared classes. Other threads might be in
+// the process of loading a shared class and have strong roots on
+// their stack to the class without having added the class to the
+// dictionary yet. This means the class will be marked during phase 1
+// but will not be unmarked during the application of the
+// RecursiveAdjustSharedObjectClosure to the SystemDictionary. Note
+// that we must not call find_shared_class with non-read-only symbols
+// as doing so can cause hash codes to be computed, destroying
+// forwarding pointers.
+class TraversePlaceholdersClosure : public OopClosure {
+ public:
+  void do_oop(oop* o) {
+    oop obj = *o;
+    if (obj->klass() == Universe::symbolKlassObj() &&
+        obj->is_shared_readonly()) {
+      symbolHandle sym((symbolOop) obj);
+      oop k = SystemDictionary::find_shared_class(sym);
+      if (k != NULL) {
+        RecursiveAdjustSharedObjectClosure clo;
+        clo.do_oop(&k);
+      }
+    }
+  }
+};
+
+
+void CompactingPermGenGen::initialize_performance_counters() {
+
+  const char* gen_name = "perm";
+
+  // Generation Counters - generation 2, 1 subspace
+  _gen_counters = new GenerationCounters(gen_name, 2, 1, &_virtual_space);
+
+  _space_counters = new CSpaceCounters(gen_name, 0,
+                                       _virtual_space.reserved_size(),
+                                      _the_space, _gen_counters);
+}
+
+void CompactingPermGenGen::update_counters() {
+  if (UsePerfData) {
+    _space_counters->update_all();
+    _gen_counters->update_all();
+  }
+}
+
+
+CompactingPermGenGen::CompactingPermGenGen(ReservedSpace rs,
+                                           ReservedSpace shared_rs,
+                                           size_t initial_byte_size,
+                                           int level, GenRemSet* remset,
+                                           ContiguousSpace* space,
+                                           PermanentGenerationSpec* spec_) :
+  OneContigSpaceCardGeneration(rs, initial_byte_size, MinPermHeapExpansion,
+                               level, remset, space) {
+
+  set_spec(spec_);
+  if (!UseSharedSpaces && !DumpSharedSpaces) {
+    spec()->disable_sharing();
+  }
+
+  // Break virtual space into address ranges for all spaces.
+
+  if (spec()->enable_shared_spaces()) {
+    shared_end = (HeapWord*)(shared_rs.base() + shared_rs.size());
+      misccode_end = shared_end;
+      misccode_bottom = misccode_end - heap_word_size(spec()->misc_code_size());
+      miscdata_end = misccode_bottom;
+      miscdata_bottom = miscdata_end - heap_word_size(spec()->misc_data_size());
+      readwrite_end = miscdata_bottom;
+      readwrite_bottom =
+        readwrite_end - heap_word_size(spec()->read_write_size());
+      readonly_end = readwrite_bottom;
+      readonly_bottom =
+        readonly_end - heap_word_size(spec()->read_only_size());
+    shared_bottom = readonly_bottom;
+    unshared_end = shared_bottom;
+    assert((char*)shared_bottom == shared_rs.base(), "shared space mismatch");
+  } else {
+    shared_end = (HeapWord*)(rs.base() + rs.size());
+      misccode_end = shared_end;
+      misccode_bottom = shared_end;
+      miscdata_end = shared_end;
+      miscdata_bottom = shared_end;
+      readwrite_end = shared_end;
+      readwrite_bottom = shared_end;
+      readonly_end = shared_end;
+      readonly_bottom = shared_end;
+    shared_bottom = shared_end;
+    unshared_end = shared_bottom;
+  }
+  unshared_bottom = (HeapWord*) rs.base();
+
+  // Verify shared and unshared spaces adjacent.
+  assert((char*)shared_bottom == rs.base()+rs.size(), "shared space mismatch");
+  assert(unshared_end > unshared_bottom, "shared space mismatch");
+
+  // Split reserved memory into pieces.
+
+  ReservedSpace ro_rs   = shared_rs.first_part(spec()->read_only_size(),
+                                              UseSharedSpaces);
+  ReservedSpace tmp_rs1 = shared_rs.last_part(spec()->read_only_size());
+  ReservedSpace rw_rs   = tmp_rs1.first_part(spec()->read_write_size(),
+                                             UseSharedSpaces);
+  ReservedSpace tmp_rs2 = tmp_rs1.last_part(spec()->read_write_size());
+  ReservedSpace md_rs   = tmp_rs2.first_part(spec()->misc_data_size(),
+                                             UseSharedSpaces);
+  ReservedSpace mc_rs   = tmp_rs2.last_part(spec()->misc_data_size());
+
+  _shared_space_size = spec()->read_only_size()
+                     + spec()->read_write_size()
+                     + spec()->misc_data_size()
+                     + spec()->misc_code_size();
+
+  // Allocate the unshared (default) space.
+  _the_space = new ContigPermSpace(_bts,
+               MemRegion(unshared_bottom, heap_word_size(initial_byte_size)));
+  if (_the_space == NULL)
+    vm_exit_during_initialization("Could not allocate an unshared"
+                                  " CompactingPermGen Space");
+
+  // Allocate shared spaces
+  if (spec()->enable_shared_spaces()) {
+
+    // If mapping a shared file, the space is not committed, don't
+    // mangle.
+    NOT_PRODUCT(bool old_ZapUnusedHeapArea = ZapUnusedHeapArea;)
+    NOT_PRODUCT(if (UseSharedSpaces) ZapUnusedHeapArea = false;)
+
+    // Commit the memory behind the shared spaces if dumping (not
+    // mapping).
+    if (DumpSharedSpaces) {
+      _ro_vs.initialize(ro_rs, spec()->read_only_size());
+      _rw_vs.initialize(rw_rs, spec()->read_write_size());
+      _md_vs.initialize(md_rs, spec()->misc_data_size());
+      _mc_vs.initialize(mc_rs, spec()->misc_code_size());
+    }
+
+    // Allocate the shared spaces.
+    _ro_bts = new BlockOffsetSharedArray(
+                  MemRegion(readonly_bottom,
+                            heap_word_size(spec()->read_only_size())),
+                  heap_word_size(spec()->read_only_size()));
+    _ro_space = new OffsetTableContigSpace(_ro_bts,
+                  MemRegion(readonly_bottom, readonly_end));
+    _rw_bts = new BlockOffsetSharedArray(
+                  MemRegion(readwrite_bottom,
+                            heap_word_size(spec()->read_write_size())),
+                  heap_word_size(spec()->read_write_size()));
+    _rw_space = new OffsetTableContigSpace(_rw_bts,
+                  MemRegion(readwrite_bottom, readwrite_end));
+
+    // Restore mangling flag.
+    NOT_PRODUCT(ZapUnusedHeapArea = old_ZapUnusedHeapArea;)
+
+    if (_ro_space == NULL || _rw_space == NULL)
+      vm_exit_during_initialization("Could not allocate a shared space");
+
+    // Cover both shared spaces entirely with cards.
+    _rs->resize_covered_region(MemRegion(readonly_bottom, readwrite_end));
+
+    if (UseSharedSpaces) {
+
+      // Map in the regions in the shared file.
+      FileMapInfo* mapinfo = FileMapInfo::current_info();
+      size_t image_alignment = mapinfo->alignment();
+      CollectedHeap* ch = Universe::heap();
+      if ((!mapinfo->map_space(ro, ro_rs, _ro_space)) ||
+          (!mapinfo->map_space(rw, rw_rs, _rw_space)) ||
+          (!mapinfo->map_space(md, md_rs, NULL))      ||
+          (!mapinfo->map_space(mc, mc_rs, NULL))      ||
+          // check the alignment constraints
+          (ch == NULL || ch->kind() != CollectedHeap::GenCollectedHeap ||
+           image_alignment !=
+           ((GenCollectedHeap*)ch)->gen_policy()->max_alignment())) {
+        // Base addresses didn't match; skip sharing, but continue
+        shared_rs.release();
+        spec()->disable_sharing();
+        // If -Xshare:on is specified, print out the error message and exit VM,
+        // otherwise, set UseSharedSpaces to false and continue.
+        if (RequireSharedSpaces) {
+          vm_exit_during_initialization("Unable to use shared archive.", NULL);
+        } else {
+          FLAG_SET_DEFAULT(UseSharedSpaces, false);
+        }
+
+        // Note: freeing the block offset array objects does not
+        // currently free up the underlying storage.
+        delete _ro_bts;
+        _ro_bts = NULL;
+        delete _ro_space;
+        _ro_space = NULL;
+        delete _rw_bts;
+        _rw_bts = NULL;
+        delete _rw_space;
+        _rw_space = NULL;
+        shared_end = (HeapWord*)(rs.base() + rs.size());
+        _rs->resize_covered_region(MemRegion(shared_bottom, shared_bottom));
+      }
+    }
+
+    // Reserved region includes shared spaces for oop.is_in_reserved().
+    _reserved.set_end(shared_end);
+
+  } else {
+    _ro_space = NULL;
+    _rw_space = NULL;
+  }
+}
+
+
+// Do a complete scan of the shared read write space to catch all
+// objects which contain references to any younger generation.  Forward
+// the pointers.  Avoid space_iterate, as actually visiting all the
+// objects in the space will page in more objects than we need.
+// Instead, use the system dictionary as strong roots into the read
+// write space.
+
+void CompactingPermGenGen::pre_adjust_pointers() {
+  if (spec()->enable_shared_spaces()) {
+    RecursiveAdjustSharedObjectClosure blk;
+    Universe::oops_do(&blk);
+    StringTable::oops_do(&blk);
+    SystemDictionary::always_strong_classes_do(&blk);
+    TraversePlaceholdersClosure tpc;
+    SystemDictionary::placeholders_do(&tpc);
+  }
+}
+
+
+#ifdef ASSERT
+class VerifyMarksClearedClosure : public ObjectClosure {
+public:
+  void do_object(oop obj) {
+    assert(SharedSkipVerify || !obj->mark()->is_marked(),
+           "Shared oop still marked?");
+  }
+};
+#endif
+
+
+void CompactingPermGenGen::post_compact() {
+#ifdef ASSERT
+  if (!SharedSkipVerify && spec()->enable_shared_spaces()) {
+    VerifyMarksClearedClosure blk;
+    rw_space()->object_iterate(&blk);
+  }
+#endif
+}
+
+
+void CompactingPermGenGen::space_iterate(SpaceClosure* blk, bool usedOnly) {
+  OneContigSpaceCardGeneration::space_iterate(blk, usedOnly);
+  if (spec()->enable_shared_spaces()) {
+#ifdef PRODUCT
+    // Making the rw_space walkable will page in the entire space, and
+    // is to be avoided. However, this is required for Verify options.
+    ShouldNotReachHere();
+#endif
+
+    blk->do_space(ro_space());
+    blk->do_space(rw_space());
+  }
+}
+
+
+void CompactingPermGenGen::print_on(outputStream* st) const {
+  OneContigSpaceCardGeneration::print_on(st);
+  if (spec()->enable_shared_spaces()) {
+    st->print("    ro");
+    ro_space()->print_on(st);
+    st->print("    rw");
+    rw_space()->print_on(st);
+  } else {
+    st->print_cr("No shared spaces configured.");
+  }
+}
+
+
+// References from the perm gen to the younger generation objects may
+// occur in static fields in Java classes or in constant pool references
+// to String objects.
+
+void CompactingPermGenGen::younger_refs_iterate(OopsInGenClosure* blk) {
+  OneContigSpaceCardGeneration::younger_refs_iterate(blk);
+  if (spec()->enable_shared_spaces()) {
+    blk->set_generation(this);
+    // ro_space has no younger gen refs.
+    _rs->younger_refs_in_space_iterate(rw_space(), blk);
+    blk->reset_generation();
+  }
+}
+
+
+// Shared spaces are addressed in pre_adjust_pointers.
+void CompactingPermGenGen::adjust_pointers() {
+  the_space()->adjust_pointers();
+}
+
+
+void CompactingPermGenGen::compact() {
+  the_space()->compact();
+}
+
+
+size_t CompactingPermGenGen::contiguous_available() const {
+  // Don't include shared spaces.
+  return OneContigSpaceCardGeneration::contiguous_available()
+         - _shared_space_size;
+}
+
+size_t CompactingPermGenGen::max_capacity() const {
+  // Don't include shared spaces.
+  assert(UseSharedSpaces || (_shared_space_size == 0),
+    "If not used, the size of shared spaces should be 0");
+  return OneContigSpaceCardGeneration::max_capacity()
+          - _shared_space_size;
+}
+
+
+
+bool CompactingPermGenGen::grow_by(size_t bytes) {
+  // Don't allow _virtual_size to expand into shared spaces.
+  size_t max_bytes = _virtual_space.uncommitted_size() - _shared_space_size;
+  if (bytes > _shared_space_size) {
+    bytes = _shared_space_size;
+  }
+  return OneContigSpaceCardGeneration::grow_by(bytes);
+}
+
+
+void CompactingPermGenGen::grow_to_reserved() {
+  // Don't allow _virtual_size to expand into shared spaces.
+  if (_virtual_space.uncommitted_size() > _shared_space_size) {
+    size_t remaining_bytes =
+      _virtual_space.uncommitted_size() - _shared_space_size;
+    bool success = OneContigSpaceCardGeneration::grow_by(remaining_bytes);
+    DEBUG_ONLY(if (!success) warning("grow to reserved failed");)
+  }
+}
+
+
+// No young generation references, clear this generation's main space's
+// card table entries.  Do NOT clear the card table entries for the
+// read-only space (always clear) or the read-write space (valuable
+// information).
+
+void CompactingPermGenGen::clear_remembered_set() {
+  _rs->clear(MemRegion(the_space()->bottom(), the_space()->end()));
+}
+
+
+// Objects in this generation's main space may have moved, invalidate
+// that space's cards.  Do NOT invalidate the card table entries for the
+// read-only or read-write spaces, as those objects never move.
+
+void CompactingPermGenGen::invalidate_remembered_set() {
+  _rs->invalidate(used_region());
+}
+
+
+void CompactingPermGenGen::verify(bool allow_dirty) {
+  the_space()->verify(allow_dirty);
+  if (!SharedSkipVerify && spec()->enable_shared_spaces()) {
+    ro_space()->verify(allow_dirty);
+    rw_space()->verify(allow_dirty);
+  }
+}
+
+
+HeapWord* CompactingPermGenGen::unshared_bottom;
+HeapWord* CompactingPermGenGen::unshared_end;
+HeapWord* CompactingPermGenGen::shared_bottom;
+HeapWord* CompactingPermGenGen::shared_end;
+HeapWord* CompactingPermGenGen::readonly_bottom;
+HeapWord* CompactingPermGenGen::readonly_end;
+HeapWord* CompactingPermGenGen::readwrite_bottom;
+HeapWord* CompactingPermGenGen::readwrite_end;
+HeapWord* CompactingPermGenGen::miscdata_bottom;
+HeapWord* CompactingPermGenGen::miscdata_end;
+HeapWord* CompactingPermGenGen::misccode_bottom;
+HeapWord* CompactingPermGenGen::misccode_end;
+
+// JVM/TI RedefineClasses() support:
+bool CompactingPermGenGen::remap_shared_readonly_as_readwrite() {
+  assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
+
+  if (UseSharedSpaces) {
+    // remap the shared readonly space to shared readwrite, private
+    FileMapInfo* mapinfo = FileMapInfo::current_info();
+    if (!mapinfo->remap_shared_readonly_as_readwrite()) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void** CompactingPermGenGen::_vtbl_list;