jdk8-mips64-public/hotspot: src/share/vm/memory/sharedHeap.cpp@2c6ef90f030a (annotated)

src/share/vm/memory/sharedHeap.cpp@2c6ef90f030a (annotated)

src/share/vm/memory/sharedHeap.cpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6972: 64ac9c55d666
child 6996: f3aeae1f9fc5
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 2000, 2014, 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/atomic.inline.hpp"
 #include "runtime/fprofiler.hpp"
 #include "runtime/java.hpp"
 #include "services/management.hpp"
 #include "utilities/copy.hpp"
 #include "utilities/workgroup.hpp"
 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
 SharedHeap* SharedHeap::_sh;
 // The set of potentially parallel tasks in root scanning.
 enum SH_process_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_ClassLoaderDataGraph_oops_do,
   SH_PS_jvmti_oops_do,
   SH_PS_CodeCache_oops_do,
   // Leave this one last.
   SH_PS_NumElements
 };
 SharedHeap::SharedHeap(CollectorPolicy* policy_) :
   CollectedHeap(),
   _collector_policy(policy_),
   _rem_set(NULL),
   _strong_roots_scope(NULL),
   _strong_roots_parity(0),
   _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
   _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 && (CMSParallelInitialMarkEnabled ||
                               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();
     }
   }
 }
 int SharedHeap::n_termination() {
   return _process_strong_tasks->n_threads();
 }
 void SharedHeap::set_n_termination(int t) {
   _process_strong_tasks->set_n_threads(t);
 }
 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(uint t) {
   assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
   _n_par_threads = t;
   _process_strong_tasks->set_n_threads(t);
 }
 #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
 SharedHeap::StrongRootsScope* SharedHeap::active_strong_roots_scope() const {
   return _strong_roots_scope;
 }
 void SharedHeap::register_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
   assert(_strong_roots_scope == NULL, "Should only have one StrongRootsScope active");
   assert(scope != NULL, "Illegal argument");
   _strong_roots_scope = scope;
 }
 void SharedHeap::unregister_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
   assert(_strong_roots_scope == scope, "Wrong scope unregistered");
   _strong_roots_scope = NULL;
 }
 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* heap, bool activate)
   : MarkScope(activate), _sh(heap), _n_workers_done_with_threads(0)
 {
   if (_active) {
     _sh->register_strong_roots_scope(this);
     _sh->change_strong_roots_parity();
     // Zero the claimed high water mark in the StringTable
     StringTable::clear_parallel_claimed_index();
   }
 }
 SharedHeap::StrongRootsScope::~StrongRootsScope() {
   if (_active) {
     _sh->unregister_strong_roots_scope(this);
   }
 }
 Monitor* SharedHeap::StrongRootsScope::_lock = new Monitor(Mutex::leaf, "StrongRootsScope lock", false);
 void SharedHeap::StrongRootsScope::mark_worker_done_with_threads(uint n_workers) {
   // The Thread work barrier is only needed by G1.
   // No need to use the barrier if this is single-threaded code.
   if (UseG1GC && n_workers > 0) {
     uint new_value = (uint)Atomic::add(1, &_n_workers_done_with_threads);
     if (new_value == n_workers) {
       // This thread is last. Notify the others.
       MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
       _lock->notify_all();
     }
   }
 }
 void SharedHeap::StrongRootsScope::wait_until_all_workers_done_with_threads(uint n_workers) {
   // No need to use the barrier if this is single-threaded code.
   if (n_workers > 0 && (uint)_n_workers_done_with_threads != n_workers) {
     MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
     while ((uint)_n_workers_done_with_threads != n_workers) {
       _lock->wait(Mutex::_no_safepoint_check_flag, 0, false);
     }
   }
 }
 void SharedHeap::process_roots(bool activate_scope,
                                ScanningOption so,
                                OopClosure* strong_roots,
                                OopClosure* weak_roots,
                                CLDClosure* strong_cld_closure,
                                CLDClosure* weak_cld_closure,
                                CodeBlobClosure* code_roots) {
   StrongRootsScope srs(this, activate_scope);
   // General roots.
   assert(_strong_roots_parity != 0, "must have called prologue code");
   assert(code_roots != NULL, "code root closure should always be set");
   // _n_termination for _process_strong_tasks should be set up stream
   // in a method not running in a GC worker.  Otherwise the GC worker
   // could be trying to change the termination condition while the task
   // is executing in another GC worker.
   // Iterating over the CLDG and the Threads are done early to allow G1 to
   // first process the strong CLDs and nmethods and then, after a barrier,
   // let the thread process the weak CLDs and nmethods.
   if (!_process_strong_tasks->is_task_claimed(SH_PS_ClassLoaderDataGraph_oops_do)) {
     ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
   }
   // Some CLDs contained in the thread frames should be considered strong.
   // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
   CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
   // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
   CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
   Threads::possibly_parallel_oops_do(strong_roots, roots_from_clds_p, roots_from_code_p);
   // This is the point where this worker thread will not find more strong CLDs/nmethods.
   // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
   active_strong_roots_scope()->mark_worker_done_with_threads(n_par_threads());
   if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
     Universe::oops_do(strong_roots);
   }
   // Global (strong) JNI handles
   if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
     JNIHandles::oops_do(strong_roots);
   if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
     ObjectSynchronizer::oops_do(strong_roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
     FlatProfiler::oops_do(strong_roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
     Management::oops_do(strong_roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
     JvmtiExport::oops_do(strong_roots);
   if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
     SystemDictionary::roots_oops_do(strong_roots, weak_roots);
   }
   // All threads execute the following. A specific chunk of buckets
   // from the StringTable are the individual tasks.
   if (weak_roots != NULL) {
     if (CollectedHeap::use_parallel_gc_threads()) {
       StringTable::possibly_parallel_oops_do(weak_roots);
     } else {
       StringTable::oops_do(weak_roots);
     }
   }
   if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
     if (so & SO_ScavengeCodeCache) {
       assert(code_roots != NULL, "must supply closure for code cache");
       // We only visit parts of the CodeCache when scavenging.
       CodeCache::scavenge_root_nmethods_do(code_roots);
     }
     if (so & SO_AllCodeCache) {
       assert(code_roots != NULL, "must supply closure for code cache");
       // CMSCollector uses this to do intermediate-strength collections.
       // We scan the entire code cache, since CodeCache::do_unloading is not called.
       CodeCache::blobs_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, !CodeBlobToOopClosure::FixRelocations));
     DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
   }
   _process_strong_tasks->all_tasks_completed();
 }
 void SharedHeap::process_all_roots(bool activate_scope,
                                    ScanningOption so,
                                    OopClosure* roots,
                                    CLDClosure* cld_closure,
                                    CodeBlobClosure* code_closure) {
   process_roots(activate_scope, so,
                 roots, roots,
                 cld_closure, cld_closure,
                 code_closure);
 }
 void SharedHeap::process_strong_roots(bool activate_scope,
                                       ScanningOption so,
                                       OopClosure* roots,
                                       CLDClosure* cld_closure,
                                       CodeBlobClosure* code_closure) {
   process_roots(activate_scope, so,
                 roots, NULL,
                 cld_closure, NULL,
                 code_closure);
 }
 class AlwaysTrueClosure: public BoolObjectClosure {
 public:
   bool do_object_b(oop p) { return true; }
 };
 static AlwaysTrueClosure always_true;
 void SharedHeap::process_weak_roots(OopClosure* root_closure) {
   // Global (weak) JNI handles
   JNIHandles::weak_oops_do(&always_true, 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() {
   CollectedHeap::post_initialize();
   ref_processing_init();
 }
 void SharedHeap::ref_processing_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@2c6ef90f030a (annotated)

src/share/vm/memory/sharedHeap.cpp