jdk8-mips64-public/hotspot: src/share/vm/memory/compactingPermGenGen.cpp@26f1542097f1 (annotated)

src/share/vm/memory/compactingPermGenGen.cpp@26f1542097f1 (annotated)

src/share/vm/memory/compactingPermGenGen.cpp

Tue, 03 Nov 2009 16:43:16 -0800

author: ysr
date: Tue, 03 Nov 2009 16:43:16 -0800
changeset 1486: 26f1542097f1
parent 726: 5251a9cd8eb8
child 1907: c18cbe5936b8
permissions: -rw-r--r--

6801625: CDS: HeapDump tests crash with internal error in compactingPermGenGen.cpp
Summary: Allow iteration over the shared spaces when using CDS, repealing previous proscription. Deferred further required CDS-related cleanups of perm gen to CR 6897789.
Reviewed-by: phh, jmasa

 /*
  * Copyright 2003-2008 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"
 // An ObjectClosure helper: 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. This helper is used when the
 // RedefineClasses() API has been called.
 class AdjustSharedObjectClosure : public ObjectClosure {
 public:
   void do_object(oop obj) {
     if (obj->is_shared_readwrite()) {
       if (obj->mark()->is_marked()) {
         obj->init_mark();         // Don't revisit this object.
         obj->adjust_pointers();   // Adjust this object's references.
       }
     }
   }
 };
 // An OopClosure helper: 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 {
  protected:
   template <class T> inline void do_oop_work(T* p) {
     oop obj = oopDesc::load_decode_heap_oop_not_null(p);
     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);
           }
         }
       }
     }
   }
  public:
   virtual void do_oop(oop* p)       { RecursiveAdjustSharedObjectClosure::do_oop_work(p); }
   virtual void do_oop(narrowOop* p) { RecursiveAdjustSharedObjectClosure::do_oop_work(p); }
 };
 // 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 {
  protected:
   template <class T> inline void do_oop_work(T* p) {
     oop obj = oopDesc::load_decode_heap_oop_not_null(p);
     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);
       }
     }
   }
  public:
   virtual void do_oop(oop* p)       { TraversePlaceholdersClosure::do_oop_work(p); }
   virtual void do_oop(narrowOop* p) { TraversePlaceholdersClosure::do_oop_work(p); }
 };
 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.
 //
 // If a RedefineClasses() call has been made, then we have to iterate
 // over the entire shared read-write space in order to find all the
 // objects that need to be forwarded. For example, it is possible for
 // an nmethod to be found and marked in GC phase-1 only for the nmethod
 // to be freed by the time we reach GC phase-3. The underlying method
 // is still marked, but we can't (easily) find it in GC phase-3 so we
 // blow up in GC phase-4. With RedefineClasses() we want replaced code
 // (EMCP or obsolete) to go away (i.e., be collectible) once it is no
 // longer being executed by any thread so we keep minimal attachments
 // to the replaced code. However, we can't guarantee when those EMCP
 // or obsolete methods will be collected so they may still be out there
 // even after we've severed our minimal attachments.
 void CompactingPermGenGen::pre_adjust_pointers() {
   if (spec()->enable_shared_spaces()) {
     if (JvmtiExport::has_redefined_a_class()) {
       // RedefineClasses() requires a brute force approach
       AdjustSharedObjectClosure blk;
       rw_space()->object_iterate(&blk);
     } else {
       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
 }
 // Do not use in time-critical operations due to the possibility of paging
 // in otherwise untouched or previously unread portions of the perm gen,
 // for instance, the shared spaces. NOTE: Because CompactingPermGenGen
 // derives from OneContigSpaceCardGeneration which is supposed to have a
 // single space, and does not override its object_iterate() method,
 // object iteration via that interface does not look at the objects in
 // the shared spaces when using CDS. This should be fixed; see CR 6897798.
 void CompactingPermGenGen::space_iterate(SpaceClosure* blk, bool usedOnly) {
   OneContigSpaceCardGeneration::space_iterate(blk, usedOnly);
   if (spec()->enable_shared_spaces()) {
     // Making the rw_space walkable will page in the entire space, and
     // is to be avoided in the case of time-critical operations.
     // However, this is required for Verify and heap dump operations.
     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;
 }
 // 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;

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/compactingPermGenGen.cpp@26f1542097f1 (annotated)

src/share/vm/memory/compactingPermGenGen.cpp