duke@435: /*
drchase@6680:  * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/symbolTable.hpp"
stefank@2314: #include "classfile/systemDictionary.hpp"
stefank@2314: #include "code/codeCache.hpp"
stefank@2314: #include "gc_interface/collectedHeap.inline.hpp"
stefank@2314: #include "memory/sharedHeap.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@6992: #include "runtime/atomic.inline.hpp"
stefank@2314: #include "runtime/fprofiler.hpp"
stefank@2314: #include "runtime/java.hpp"
stefank@2314: #include "services/management.hpp"
stefank@2314: #include "utilities/copy.hpp"
stefank@2314: #include "utilities/workgroup.hpp"
duke@435: 
drchase@6680: PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
drchase@6680: 
duke@435: SharedHeap* SharedHeap::_sh;
duke@435: 
stefank@6992: // The set of potentially parallel tasks in root scanning.
stefank@6992: enum SH_process_roots_tasks {
duke@435:   SH_PS_Universe_oops_do,
duke@435:   SH_PS_JNIHandles_oops_do,
duke@435:   SH_PS_ObjectSynchronizer_oops_do,
duke@435:   SH_PS_FlatProfiler_oops_do,
duke@435:   SH_PS_Management_oops_do,
duke@435:   SH_PS_SystemDictionary_oops_do,
stefank@5194:   SH_PS_ClassLoaderDataGraph_oops_do,
duke@435:   SH_PS_jvmti_oops_do,
duke@435:   SH_PS_CodeCache_oops_do,
duke@435:   // Leave this one last.
duke@435:   SH_PS_NumElements
duke@435: };
duke@435: 
duke@435: SharedHeap::SharedHeap(CollectorPolicy* policy_) :
duke@435:   CollectedHeap(),
duke@435:   _collector_policy(policy_),
coleenp@4037:   _rem_set(NULL),
stefank@6992:   _strong_roots_scope(NULL),
duke@435:   _strong_roots_parity(0),
duke@435:   _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
jmasa@2188:   _workers(NULL)
duke@435: {
duke@435:   if (_process_strong_tasks == NULL || !_process_strong_tasks->valid()) {
duke@435:     vm_exit_during_initialization("Failed necessary allocation.");
duke@435:   }
duke@435:   _sh = this;  // ch is static, should be set only once.
duke@435:   if ((UseParNewGC ||
jmasa@5461:       (UseConcMarkSweepGC && (CMSParallelInitialMarkEnabled ||
jmasa@5461:                               CMSParallelRemarkEnabled)) ||
ysr@777:        UseG1GC) &&
duke@435:       ParallelGCThreads > 0) {
jmasa@2188:     _workers = new FlexibleWorkGang("Parallel GC Threads", ParallelGCThreads,
ysr@777:                             /* are_GC_task_threads */true,
ysr@777:                             /* are_ConcurrentGC_threads */false);
duke@435:     if (_workers == NULL) {
duke@435:       vm_exit_during_initialization("Failed necessary allocation.");
jmasa@2188:     } else {
jmasa@2188:       _workers->initialize_workers();
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
jmasa@3294: int SharedHeap::n_termination() {
jmasa@3294:   return _process_strong_tasks->n_threads();
jmasa@3294: }
jmasa@3294: 
jmasa@3294: void SharedHeap::set_n_termination(int t) {
jmasa@3294:   _process_strong_tasks->set_n_threads(t);
jmasa@3294: }
jmasa@3294: 
ysr@777: bool SharedHeap::heap_lock_held_for_gc() {
ysr@777:   Thread* t = Thread::current();
ysr@777:   return    Heap_lock->owned_by_self()
ysr@777:          || (   (t->is_GC_task_thread() ||  t->is_VM_thread())
ysr@777:              && _thread_holds_heap_lock_for_gc);
ysr@777: }
duke@435: 
jmasa@3357: void SharedHeap::set_par_threads(uint t) {
jmasa@2188:   assert(t == 0 || !UseSerialGC, "Cannot have parallel threads");
duke@435:   _n_par_threads = t;
jmasa@2188:   _process_strong_tasks->set_n_threads(t);
duke@435: }
duke@435: 
jmasa@2909: #ifdef ASSERT
jmasa@2909: class AssertNonScavengableClosure: public OopClosure {
jmasa@2909: public:
jmasa@2909:   virtual void do_oop(oop* p) {
jmasa@2909:     assert(!Universe::heap()->is_in_partial_collection(*p),
jmasa@2909:       "Referent should not be scavengable.");  }
jmasa@2909:   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
jmasa@2909: };
jmasa@2909: static AssertNonScavengableClosure assert_is_non_scavengable_closure;
jmasa@2909: #endif
jmasa@2909: 
stefank@6992: SharedHeap::StrongRootsScope* SharedHeap::active_strong_roots_scope() const {
stefank@6992:   return _strong_roots_scope;
stefank@6992: }
stefank@6992: void SharedHeap::register_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
stefank@6992:   assert(_strong_roots_scope == NULL, "Should only have one StrongRootsScope active");
stefank@6992:   assert(scope != NULL, "Illegal argument");
stefank@6992:   _strong_roots_scope = scope;
stefank@6992: }
stefank@6992: void SharedHeap::unregister_strong_roots_scope(SharedHeap::StrongRootsScope* scope) {
stefank@6992:   assert(_strong_roots_scope == scope, "Wrong scope unregistered");
stefank@6992:   _strong_roots_scope = NULL;
stefank@6992: }
stefank@6992: 
duke@435: void SharedHeap::change_strong_roots_parity() {
duke@435:   // Also set the new collection parity.
duke@435:   assert(_strong_roots_parity >= 0 && _strong_roots_parity <= 2,
duke@435:          "Not in range.");
duke@435:   _strong_roots_parity++;
duke@435:   if (_strong_roots_parity == 3) _strong_roots_parity = 1;
duke@435:   assert(_strong_roots_parity >= 1 && _strong_roots_parity <= 2,
duke@435:          "Not in range.");
duke@435: }
duke@435: 
stefank@6992: SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* heap, bool activate)
stefank@6992:   : MarkScope(activate), _sh(heap), _n_workers_done_with_threads(0)
jrose@1424: {
jrose@1424:   if (_active) {
stefank@6992:     _sh->register_strong_roots_scope(this);
stefank@6992:     _sh->change_strong_roots_parity();
johnc@5277:     // Zero the claimed high water mark in the StringTable
johnc@5277:     StringTable::clear_parallel_claimed_index();
jrose@1424:   }
jrose@1424: }
jrose@1424: 
jrose@1424: SharedHeap::StrongRootsScope::~StrongRootsScope() {
stefank@6992:   if (_active) {
stefank@6992:     _sh->unregister_strong_roots_scope(this);
stefank@6992:   }
stefank@6992: }
stefank@6992: 
stefank@6992: Monitor* SharedHeap::StrongRootsScope::_lock = new Monitor(Mutex::leaf, "StrongRootsScope lock", false);
stefank@6992: 
stefank@6992: void SharedHeap::StrongRootsScope::mark_worker_done_with_threads(uint n_workers) {
stefank@6992:   // The Thread work barrier is only needed by G1.
stefank@6992:   // No need to use the barrier if this is single-threaded code.
stefank@6992:   if (UseG1GC && n_workers > 0) {
stefank@6992:     uint new_value = (uint)Atomic::add(1, &_n_workers_done_with_threads);
stefank@6992:     if (new_value == n_workers) {
stefank@6992:       // This thread is last. Notify the others.
stefank@6992:       MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
stefank@6992:       _lock->notify_all();
stefank@6992:     }
stefank@6992:   }
stefank@6992: }
stefank@6992: 
stefank@6992: void SharedHeap::StrongRootsScope::wait_until_all_workers_done_with_threads(uint n_workers) {
stefank@6992:   // No need to use the barrier if this is single-threaded code.
stefank@6992:   if (n_workers > 0 && (uint)_n_workers_done_with_threads != n_workers) {
stefank@6992:     MonitorLockerEx ml(_lock, Mutex::_no_safepoint_check_flag);
stefank@6992:     while ((uint)_n_workers_done_with_threads != n_workers) {
stefank@6992:       _lock->wait(Mutex::_no_safepoint_check_flag, 0, false);
stefank@6992:     }
stefank@6992:   }
stefank@6992: }
stefank@6992: 
stefank@6992: void SharedHeap::process_roots(bool activate_scope,
stefank@6992:                                ScanningOption so,
stefank@6992:                                OopClosure* strong_roots,
stefank@6992:                                OopClosure* weak_roots,
stefank@6992:                                CLDClosure* strong_cld_closure,
stefank@6992:                                CLDClosure* weak_cld_closure,
stefank@6992:                                CodeBlobClosure* code_roots) {
stefank@6992:   StrongRootsScope srs(this, activate_scope);
stefank@6992: 
stefank@6992:   // General roots.
stefank@6992:   assert(_strong_roots_parity != 0, "must have called prologue code");
stefank@6992:   assert(code_roots != NULL, "code root closure should always be set");
stefank@6992:   // _n_termination for _process_strong_tasks should be set up stream
stefank@6992:   // in a method not running in a GC worker.  Otherwise the GC worker
stefank@6992:   // could be trying to change the termination condition while the task
stefank@6992:   // is executing in another GC worker.
stefank@6992: 
stefank@6992:   // Iterating over the CLDG and the Threads are done early to allow G1 to
stefank@6992:   // first process the strong CLDs and nmethods and then, after a barrier,
stefank@6992:   // let the thread process the weak CLDs and nmethods.
stefank@6992: 
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_ClassLoaderDataGraph_oops_do)) {
stefank@6992:     ClassLoaderDataGraph::roots_cld_do(strong_cld_closure, weak_cld_closure);
stefank@6992:   }
stefank@6992: 
stefank@6992:   // Some CLDs contained in the thread frames should be considered strong.
stefank@6992:   // Don't process them if they will be processed during the ClassLoaderDataGraph phase.
stefank@6992:   CLDClosure* roots_from_clds_p = (strong_cld_closure != weak_cld_closure) ? strong_cld_closure : NULL;
stefank@6992:   // Only process code roots from thread stacks if we aren't visiting the entire CodeCache anyway
stefank@6992:   CodeBlobClosure* roots_from_code_p = (so & SO_AllCodeCache) ? NULL : code_roots;
stefank@6992: 
stefank@6992:   Threads::possibly_parallel_oops_do(strong_roots, roots_from_clds_p, roots_from_code_p);
stefank@6992: 
stefank@6992:   // This is the point where this worker thread will not find more strong CLDs/nmethods.
stefank@6992:   // Report this so G1 can synchronize the strong and weak CLDs/nmethods processing.
stefank@6992:   active_strong_roots_scope()->mark_worker_done_with_threads(n_par_threads());
stefank@6992: 
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
stefank@6992:     Universe::oops_do(strong_roots);
stefank@6992:   }
stefank@6992:   // Global (strong) JNI handles
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
stefank@6992:     JNIHandles::oops_do(strong_roots);
stefank@6992: 
stefank@6992:   if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
stefank@6992:     ObjectSynchronizer::oops_do(strong_roots);
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
stefank@6992:     FlatProfiler::oops_do(strong_roots);
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
stefank@6992:     Management::oops_do(strong_roots);
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
stefank@6992:     JvmtiExport::oops_do(strong_roots);
stefank@6992: 
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
stefank@6992:     SystemDictionary::roots_oops_do(strong_roots, weak_roots);
stefank@6992:   }
stefank@6992: 
stefank@6992:   // All threads execute the following. A specific chunk of buckets
stefank@6992:   // from the StringTable are the individual tasks.
stefank@6992:   if (weak_roots != NULL) {
stefank@6992:     if (CollectedHeap::use_parallel_gc_threads()) {
stefank@6992:       StringTable::possibly_parallel_oops_do(weak_roots);
stefank@6992:     } else {
stefank@6992:       StringTable::oops_do(weak_roots);
stefank@6992:     }
stefank@6992:   }
stefank@6992: 
stefank@6992:   if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
stefank@6992:     if (so & SO_ScavengeCodeCache) {
stefank@6992:       assert(code_roots != NULL, "must supply closure for code cache");
stefank@6992: 
stefank@6992:       // We only visit parts of the CodeCache when scavenging.
stefank@6992:       CodeCache::scavenge_root_nmethods_do(code_roots);
stefank@6992:     }
stefank@6992:     if (so & SO_AllCodeCache) {
stefank@6992:       assert(code_roots != NULL, "must supply closure for code cache");
stefank@6992: 
stefank@6992:       // CMSCollector uses this to do intermediate-strength collections.
stefank@6992:       // We scan the entire code cache, since CodeCache::do_unloading is not called.
stefank@6992:       CodeCache::blobs_do(code_roots);
stefank@6992:     }
stefank@6992:     // Verify that the code cache contents are not subject to
stefank@6992:     // movement by a scavenging collection.
stefank@6992:     DEBUG_ONLY(CodeBlobToOopClosure assert_code_is_non_scavengable(&assert_is_non_scavengable_closure, !CodeBlobToOopClosure::FixRelocations));
stefank@6992:     DEBUG_ONLY(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_non_scavengable));
stefank@6992:   }
stefank@6992: 
stefank@6992:   _process_strong_tasks->all_tasks_completed();
stefank@6992: }
stefank@6992: 
stefank@6992: void SharedHeap::process_all_roots(bool activate_scope,
stefank@6992:                                    ScanningOption so,
stefank@6992:                                    OopClosure* roots,
stefank@6992:                                    CLDClosure* cld_closure,
stefank@6992:                                    CodeBlobClosure* code_closure) {
stefank@6992:   process_roots(activate_scope, so,
stefank@6992:                 roots, roots,
stefank@6992:                 cld_closure, cld_closure,
stefank@6992:                 code_closure);
jrose@1424: }
jrose@1424: 
jrose@1424: void SharedHeap::process_strong_roots(bool activate_scope,
duke@435:                                       ScanningOption so,
duke@435:                                       OopClosure* roots,
stefank@6992:                                       CLDClosure* cld_closure,
stefank@6992:                                       CodeBlobClosure* code_closure) {
stefank@6992:   process_roots(activate_scope, so,
stefank@6992:                 roots, NULL,
stefank@6992:                 cld_closure, NULL,
stefank@6992:                 code_closure);
stefank@6992: }
coleenp@4037: 
duke@435: 
duke@435: class AlwaysTrueClosure: public BoolObjectClosure {
duke@435: public:
duke@435:   bool do_object_b(oop p) { return true; }
duke@435: };
duke@435: static AlwaysTrueClosure always_true;
duke@435: 
stefank@6971: void SharedHeap::process_weak_roots(OopClosure* root_closure) {
duke@435:   // Global (weak) JNI handles
duke@435:   JNIHandles::weak_oops_do(&always_true, root_closure);
stefank@5011: }
duke@435: 
duke@435: void SharedHeap::set_barrier_set(BarrierSet* bs) {
duke@435:   _barrier_set = bs;
duke@435:   // Cached barrier set for fast access in oops
duke@435:   oopDesc::set_bs(bs);
duke@435: }
duke@435: 
duke@435: void SharedHeap::post_initialize() {
jwilhelm@6085:   CollectedHeap::post_initialize();
duke@435:   ref_processing_init();
duke@435: }
duke@435: 
coleenp@4037: void SharedHeap::ref_processing_init() {}
duke@435: 
duke@435: // Some utilities.
ysr@777: void SharedHeap::print_size_transition(outputStream* out,
ysr@777:                                        size_t bytes_before,
duke@435:                                        size_t bytes_after,
duke@435:                                        size_t capacity) {
ysr@777:   out->print(" %d%s->%d%s(%d%s)",
duke@435:              byte_size_in_proper_unit(bytes_before),
duke@435:              proper_unit_for_byte_size(bytes_before),
duke@435:              byte_size_in_proper_unit(bytes_after),
duke@435:              proper_unit_for_byte_size(bytes_after),
duke@435:              byte_size_in_proper_unit(capacity),
duke@435:              proper_unit_for_byte_size(capacity));
duke@435: }