jdk8-mips64-public/hotspot: src/share/vm/memory/sharedHeap.cpp@d06a2d7fcd5b (annotated)

src/share/vm/memory/sharedHeap.cpp@d06a2d7fcd5b (annotated)

src/share/vm/memory/sharedHeap.cpp

Mon, 21 Nov 2011 07:47:34 +0100

author: brutisso
date: Mon, 21 Nov 2011 07:47:34 +0100
changeset 3290: d06a2d7fcd5b
parent 3115: c2bf0120ee5d
child 3294: bca17e38de00
permissions: -rw-r--r--

7110718: -XX:MarkSweepAlwaysCompactCount=0 crashes the JVM
Summary: Interpret MarkSweepAlwaysCompactCount < 1 as never do full compaction
Reviewed-by: ysr, tonyp, jmasa, johnc

 /*
  * Copyright (c) 2000, 2011, 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.
  *
  */
 #include "precompiled.hpp"
 #include "classfile/symbolTable.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "code/codeCache.hpp"
 #include "gc_interface/collectedHeap.inline.hpp"
 #include "memory/sharedHeap.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/fprofiler.hpp"
 #include "runtime/java.hpp"
 #include "services/management.hpp"
 #include "utilities/copy.hpp"
 #include "utilities/workgroup.hpp"
 SharedHeap* SharedHeap::_sh;
 // The set of potentially parallel tasks in strong root scanning.
 enum SH_process_strong_roots_tasks {
   SH_PS_Universe_oops_do,
   SH_PS_JNIHandles_oops_do,
   SH_PS_ObjectSynchronizer_oops_do,
   SH_PS_FlatProfiler_oops_do,
   SH_PS_Management_oops_do,
   SH_PS_SystemDictionary_oops_do,
   SH_PS_jvmti_oops_do,
   SH_PS_StringTable_oops_do,
   SH_PS_CodeCache_oops_do,
   // Leave this one last.
   SH_PS_NumElements
 };
 SharedHeap::SharedHeap(CollectorPolicy* policy_) :
   CollectedHeap(),
   _collector_policy(policy_),
   _perm_gen(NULL), _rem_set(NULL),
   _strong_roots_parity(0),
   _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
   _n_par_threads(0),
   _workers(NULL)
 {
   if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
     vm_exit_during_initialization("Failed necessary allocation.");
   }
   _sh = this;  // ch is static, should be set only once.
   if ((UseParNewGC ||
       (UseConcMarkSweepGC && CMSParallelRemarkEnabled) ||
        UseG1GC) &&
       ParallelGCThreads > 0) {
     _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,
                             /* are_GC_task_threads */true,
                             /* are_ConcurrentGC_threads */false);
     if (_workers == NULL) {
       vm_exit_during_initialization("Failed necessary allocation.");
     } else {
       _workers->initialize_workers();
     }
   }
 }
 bool SharedHeap::heap_lock_held_for_gc() {
   Thread* t = Thread::current();
   return    Heap_lock->owned_by_self()
          || (   (t->is_GC_task_thread() ||  t->is_VM_thread())
              && _thread_holds_heap_lock_for_gc);
 }
 void SharedHeap::set_par_threads(int t) {
   assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
   _n_par_threads = t;
   _process_strong_tasks->set_n_threads(t);
 }
 class AssertIsPermClosure: public OopClosure {
 public:
   virtual void do_oop(oop* p) {
     assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
   }
   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
 };
 static AssertIsPermClosure assert_is_perm_closure;
 #ifdef ASSERT
 class AssertNonScavengableClosure: public OopClosure {
 public:
   virtual void do_oop(oop* p) {
     assert(!Universe::heap()->is_in_partial_collection(*p),
       "Referent should not be scavengable.");  }
   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
 };
 static AssertNonScavengableClosure assert_is_non_scavengable_closure;
 #endif
 void SharedHeap::change_strong_roots_parity() {
   // Also set the new collection parity.
   assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
          "Not in range.");
   _strong_roots_parity++;
   if (_strong_roots_parity == 3) _strong_roots_parity = 1;
   assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
          "Not in range.");
 }
 SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate)
   : MarkScope(activate)
 {
   if (_active) {
     outer->change_strong_roots_parity();
   }
 }
 SharedHeap::StrongRootsScope::~StrongRootsScope() {
   // nothing particular
 }
 void SharedHeap::process_strong_roots(bool activate_scope,
                                       bool collecting_perm_gen,
                                       ScanningOption so,
                                       OopClosure* roots,
                                       CodeBlobClosure* code_roots,
                                       OopsInGenClosure* perm_blk) {
   StrongRootsScope srs(this, activate_scope);
   // General strong roots.
   assert(_strong_roots_parity != 0, "must have called prologue code");
   if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
     Universe::oops_do(roots);
     // Consider perm-gen discovered lists to be strong.
     perm_gen()->ref_processor()->weak_oops_do(roots);
   }
   // Global (strong) JNI handles
   if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
     JNIHandles::oops_do(roots);
   // All threads execute this; the individual threads are task groups.
   if (ParallelGCThreads > 0) {
     Threads::possibly_parallel_oops_do(roots, code_roots);
   } else {
     Threads::oops_do(roots, code_roots);
   }
   if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
     ObjectSynchronizer::oops_do(roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
     FlatProfiler::oops_do(roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
     Management::oops_do(roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
     JvmtiExport::oops_do(roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
     if (so & SO_AllClasses) {
       SystemDictionary::oops_do(roots);
     } else if (so & SO_SystemClasses) {
       SystemDictionary::always_strong_oops_do(roots);
     }
   }
   if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) {
     if (so & SO_Strings || (!collecting_perm_gen && !JavaObjectsInPerm)) {
       StringTable::oops_do(roots);
     }
     if (JavaObjectsInPerm) {
       // Verify the string table contents are in the perm gen
       NOT_PRODUCT(StringTable::oops_do(&assert_is_perm_closure));
     }
   }
   if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
     if (so & SO_CodeCache) {
       // (Currently, CMSCollector uses this to do intermediate-strength collections.)
       assert(collecting_perm_gen, "scanning all of code cache");
       assert(code_roots != NULL, "must supply closure for code cache");
       if (code_roots != NULL) {
         CodeCache::blobs_do(code_roots);
       }
     } else if (so & (SO_SystemClasses|SO_AllClasses)) {
       if (!collecting_perm_gen) {
         // If we are collecting from class statics, but we are not going to
         // visit all of the CodeCache, collect from the non-perm roots if any.
         // This makes the code cache function temporarily as a source of strong
         // roots for oops, until the next major collection.
         //
         // If collecting_perm_gen is true, we require that this phase will call
         // CodeCache::do_unloading.  This will kill off nmethods with expired
         // weak references, such as stale invokedynamic targets.
         CodeCache::scavenge_root_nmethods_do(code_roots);
       }
     }
     // Verify that the code cache contents are not subject to
     // movement by a scavenging collection.
     DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, /*do_marking=*/ false));
     DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
   }
   if (!collecting_perm_gen) {
     // All threads perform this; coordination is handled internally.
     rem_set()->younger_refs_iterate(perm_gen(), perm_blk);
   }
   _process_strong_tasks->all_tasks_completed();
 }
 class AlwaysTrueClosure: public BoolObjectClosure {
 public:
   void do_object(oop p) { ShouldNotReachHere(); }
   bool do_object_b(oop p) { return true; }
 };
 static AlwaysTrueClosure always_true;
 class SkipAdjustingSharedStrings: public OopClosure {
   OopClosure* _clo;
 public:
   SkipAdjustingSharedStrings(OopClosure* clo) : _clo(clo) {}
   virtual void do_oop(oop* p) {
     oop o = (*p);
     if (!o->is_shared_readwrite()) {
       _clo->do_oop(p);
     }
   }
   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
 };
 // Unmarked shared Strings in the StringTable (which got there due to
 // being in the constant pools of as-yet unloaded shared classes) were
 // not marked and therefore did not have their mark words preserved.
 // These entries are also deliberately not purged from the string
 // table during unloading of unmarked strings. If an identity hash
 // code was computed for any of these objects, it will not have been
 // cleared to zero during the forwarding process or by the
 // RecursiveAdjustSharedObjectClosure, and will be confused by the
 // adjusting process as a forwarding pointer. We need to skip
 // forwarding StringTable entries which contain unmarked shared
 // Strings. Actually, since shared strings won't be moving, we can
 // just skip adjusting any shared entries in the string table.
 void SharedHeap::process_weak_roots(OopClosure* root_closure,
                                     CodeBlobClosure* code_roots,
                                     OopClosure* non_root_closure) {
   // Global (weak) JNI handles
   JNIHandles::weak_oops_do(&always_true, root_closure);
   CodeCache::blobs_do(code_roots);
   if (UseSharedSpaces && !DumpSharedSpaces) {
     SkipAdjustingSharedStrings skip_closure(root_closure);
     StringTable::oops_do(&skip_closure);
   } else {
     StringTable::oops_do(root_closure);
   }
 }
 void SharedHeap::set_barrier_set(BarrierSet* bs) {
   _barrier_set = bs;
   // Cached barrier set for fast access in oops
   oopDesc::set_bs(bs);
 }
 void SharedHeap::post_initialize() {
   ref_processing_init();
 }
 void SharedHeap::ref_processing_init() {
   perm_gen()->ref_processor_init();
 }
 // Some utilities.
 void SharedHeap::print_size_transition(outputStream* out,
                                        size_t bytes_before,
                                        size_t bytes_after,
                                        size_t capacity) {
   out->print(" %d%s->%d%s(%d%s)",
              byte_size_in_proper_unit(bytes_before),
              proper_unit_for_byte_size(bytes_before),
              byte_size_in_proper_unit(bytes_after),
              proper_unit_for_byte_size(bytes_after),
              byte_size_in_proper_unit(capacity),
              proper_unit_for_byte_size(capacity));
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/memory/sharedHeap.cpp@d06a2d7fcd5b (annotated)

src/share/vm/memory/sharedHeap.cpp