duke@435: /*
xdono@1014:  * Copyright 2000-2009 Sun Microsystems, Inc.  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:  *
duke@435:  * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@435:  * CA 95054 USA or visit www.sun.com if you need additional information or
duke@435:  * have any questions.
duke@435:  *
duke@435:  */
duke@435: 
duke@435: # include "incls/_precompiled.incl"
duke@435: # include "incls/_sharedHeap.cpp.incl"
duke@435: 
duke@435: SharedHeap* SharedHeap::_sh;
duke@435: 
duke@435: // The set of potentially parallel tasks in strong root scanning.
duke@435: enum SH_process_strong_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,
duke@435:   SH_PS_jvmti_oops_do,
duke@435:   SH_PS_vmSymbols_oops_do,
duke@435:   SH_PS_SymbolTable_oops_do,
duke@435:   SH_PS_StringTable_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_),
duke@435:   _perm_gen(NULL), _rem_set(NULL),
duke@435:   _strong_roots_parity(0),
duke@435:   _process_strong_tasks(new SubTasksDone(SH_PS_NumElements)),
duke@435:   _workers(NULL), _n_par_threads(0)
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 ||
ysr@777:       (UseConcMarkSweepGC && CMSParallelRemarkEnabled) ||
ysr@777:        UseG1GC) &&
duke@435:       ParallelGCThreads > 0) {
ysr@777:     _workers = new WorkGang("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.");
duke@435:     }
duke@435:   }
duke@435: }
duke@435: 
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: 
duke@435: void SharedHeap::set_par_threads(int t) {
duke@435:   _n_par_threads = t;
duke@435:   _process_strong_tasks->set_par_threads(t);
duke@435: }
duke@435: 
duke@435: class AssertIsPermClosure: public OopClosure {
duke@435: public:
coleenp@548:   virtual void do_oop(oop* p) {
duke@435:     assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
duke@435:   }
coleenp@548:   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
duke@435: };
duke@435: static AssertIsPermClosure assert_is_perm_closure;
duke@435: 
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: 
jrose@1424: SharedHeap::StrongRootsScope::StrongRootsScope(SharedHeap* outer, bool activate)
jrose@1424:   : MarkScope(activate)
jrose@1424: {
jrose@1424:   if (_active) {
jrose@1424:     outer->change_strong_roots_parity();
jrose@1424:   }
jrose@1424: }
jrose@1424: 
jrose@1424: SharedHeap::StrongRootsScope::~StrongRootsScope() {
jrose@1424:   // nothing particular
jrose@1424: }
jrose@1424: 
jrose@1424: void SharedHeap::process_strong_roots(bool activate_scope,
jrose@1424:                                       bool collecting_perm_gen,
duke@435:                                       ScanningOption so,
duke@435:                                       OopClosure* roots,
jrose@1424:                                       CodeBlobClosure* code_roots,
duke@435:                                       OopsInGenClosure* perm_blk) {
jrose@1424:   StrongRootsScope srs(this, activate_scope);
duke@435:   // General strong roots.
jrose@1424:   assert(_strong_roots_parity != 0, "must have called prologue code");
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_Universe_oops_do)) {
duke@435:     Universe::oops_do(roots);
duke@435:     ReferenceProcessor::oops_do(roots);
duke@435:     // Consider perm-gen discovered lists to be strong.
duke@435:     perm_gen()->ref_processor()->weak_oops_do(roots);
duke@435:   }
duke@435:   // Global (strong) JNI handles
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_JNIHandles_oops_do))
duke@435:     JNIHandles::oops_do(roots);
duke@435:   // All threads execute this; the individual threads are task groups.
duke@435:   if (ParallelGCThreads > 0) {
jrose@1424:     Threads::possibly_parallel_oops_do(roots, code_roots);
duke@435:   } else {
jrose@1424:     Threads::oops_do(roots, code_roots);
duke@435:   }
duke@435:   if (!_process_strong_tasks-> is_task_claimed(SH_PS_ObjectSynchronizer_oops_do))
duke@435:     ObjectSynchronizer::oops_do(roots);
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_FlatProfiler_oops_do))
duke@435:     FlatProfiler::oops_do(roots);
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_Management_oops_do))
duke@435:     Management::oops_do(roots);
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_jvmti_oops_do))
duke@435:     JvmtiExport::oops_do(roots);
duke@435: 
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_SystemDictionary_oops_do)) {
duke@435:     if (so & SO_AllClasses) {
duke@435:       SystemDictionary::oops_do(roots);
duke@435:     } else
duke@435:       if (so & SO_SystemClasses) {
duke@435:         SystemDictionary::always_strong_oops_do(roots);
duke@435:       }
duke@435:   }
duke@435: 
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_SymbolTable_oops_do)) {
duke@435:     if (so & SO_Symbols) {
duke@435:       SymbolTable::oops_do(roots);
duke@435:     }
duke@435:     // Verify if the symbol table contents are in the perm gen
duke@435:     NOT_PRODUCT(SymbolTable::oops_do(&assert_is_perm_closure));
duke@435:   }
duke@435: 
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_StringTable_oops_do)) {
duke@435:      if (so & SO_Strings) {
duke@435:        StringTable::oops_do(roots);
duke@435:      }
duke@435:     // Verify if the string table contents are in the perm gen
duke@435:     NOT_PRODUCT(StringTable::oops_do(&assert_is_perm_closure));
duke@435:   }
duke@435: 
duke@435:   if (!_process_strong_tasks->is_task_claimed(SH_PS_CodeCache_oops_do)) {
jrose@1424:     if (so & SO_CodeCache) {
jrose@1424:       // (Currently, CMSCollector uses this to do intermediate-strength collections.)
jrose@1424:       assert(collecting_perm_gen, "scanning all of code cache");
jrose@1424:       assert(code_roots != NULL, "must supply closure for code cache");
jrose@1424:       if (code_roots != NULL) {
jrose@1424:         CodeCache::blobs_do(code_roots);
jrose@1424:       }
jrose@1424:     } else if (so & (SO_SystemClasses|SO_AllClasses)) {
jrose@1424:       if (!collecting_perm_gen) {
jrose@1424:         // If we are collecting from class statics, but we are not going to
jrose@1424:         // visit all of the CodeCache, collect from the non-perm roots if any.
jrose@1424:         // This makes the code cache function temporarily as a source of strong
jrose@1424:         // roots for oops, until the next major collection.
jrose@1424:         //
jrose@1424:         // If collecting_perm_gen is true, we require that this phase will call
jrose@1424:         // CodeCache::do_unloading.  This will kill off nmethods with expired
jrose@1424:         // weak references, such as stale invokedynamic targets.
jrose@1424:         CodeCache::scavenge_root_nmethods_do(code_roots);
jrose@1424:       }
jrose@1424:     }
duke@435:     // Verify if the code cache contents are in the perm gen
jrose@1424:     NOT_PRODUCT(CodeBlobToOopClosure assert_code_is_perm(&assert_is_perm_closure, /*do_marking=*/ false));
jrose@1424:     NOT_PRODUCT(CodeCache::asserted_non_scavengable_nmethods_do(&assert_code_is_perm));
duke@435:   }
duke@435: 
duke@435:   // Roots that should point only into permanent generation.
duke@435:   {
duke@435:     OopClosure* blk = NULL;
duke@435:     if (collecting_perm_gen) {
duke@435:       blk = roots;
duke@435:     } else {
duke@435:       debug_only(blk = &assert_is_perm_closure);
duke@435:     }
duke@435:     if (blk != NULL) {
duke@435:       if (!_process_strong_tasks->is_task_claimed(SH_PS_vmSymbols_oops_do))
duke@435:         vmSymbols::oops_do(blk);
duke@435:     }
duke@435:   }
duke@435: 
duke@435:   if (!collecting_perm_gen) {
duke@435:     // All threads perform this; coordination is handled internally.
duke@435: 
duke@435:     rem_set()->younger_refs_iterate(perm_gen(), perm_blk);
duke@435:   }
duke@435:   _process_strong_tasks->all_tasks_completed();
duke@435: }
duke@435: 
duke@435: class AlwaysTrueClosure: public BoolObjectClosure {
duke@435: public:
duke@435:   void do_object(oop p) { ShouldNotReachHere(); }
duke@435:   bool do_object_b(oop p) { return true; }
duke@435: };
duke@435: static AlwaysTrueClosure always_true;
duke@435: 
duke@435: class SkipAdjustingSharedStrings: public OopClosure {
duke@435:   OopClosure* _clo;
duke@435: public:
duke@435:   SkipAdjustingSharedStrings(OopClosure* clo) : _clo(clo) {}
duke@435: 
coleenp@548:   virtual void do_oop(oop* p) {
duke@435:     oop o = (*p);
duke@435:     if (!o->is_shared_readwrite()) {
duke@435:       _clo->do_oop(p);
duke@435:     }
duke@435:   }
coleenp@548:   virtual void do_oop(narrowOop* p) { ShouldNotReachHere(); }
duke@435: };
duke@435: 
duke@435: // Unmarked shared Strings in the StringTable (which got there due to
duke@435: // being in the constant pools of as-yet unloaded shared classes) were
duke@435: // not marked and therefore did not have their mark words preserved.
duke@435: // These entries are also deliberately not purged from the string
duke@435: // table during unloading of unmarked strings. If an identity hash
duke@435: // code was computed for any of these objects, it will not have been
duke@435: // cleared to zero during the forwarding process or by the
duke@435: // RecursiveAdjustSharedObjectClosure, and will be confused by the
duke@435: // adjusting process as a forwarding pointer. We need to skip
duke@435: // forwarding StringTable entries which contain unmarked shared
duke@435: // Strings. Actually, since shared strings won't be moving, we can
duke@435: // just skip adjusting any shared entries in the string table.
duke@435: 
duke@435: void SharedHeap::process_weak_roots(OopClosure* root_closure,
jrose@1424:                                     CodeBlobClosure* code_roots,
duke@435:                                     OopClosure* non_root_closure) {
duke@435:   // Global (weak) JNI handles
duke@435:   JNIHandles::weak_oops_do(&always_true, root_closure);
duke@435: 
jrose@1424:   CodeCache::blobs_do(code_roots);
duke@435:   SymbolTable::oops_do(root_closure);
duke@435:   if (UseSharedSpaces && !DumpSharedSpaces) {
duke@435:     SkipAdjustingSharedStrings skip_closure(root_closure);
duke@435:     StringTable::oops_do(&skip_closure);
duke@435:   } else {
duke@435:     StringTable::oops_do(root_closure);
duke@435:   }
duke@435: }
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() {
duke@435:   ref_processing_init();
duke@435: }
duke@435: 
duke@435: void SharedHeap::ref_processing_init() {
duke@435:   perm_gen()->ref_processor_init();
duke@435: }
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: }