Fri, 25 Sep 2009 12:17:06 -0700
Merge
1 /*
2 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24 # include "incls/_precompiled.incl"
25 # include "incls/_vmGCOperations.cpp.incl"
27 HS_DTRACE_PROBE_DECL1(hotspot, gc__begin, bool);
28 HS_DTRACE_PROBE_DECL(hotspot, gc__end);
30 // The same dtrace probe can't be inserted in two different files, so we
31 // have to call it here, so it's only in one file. Can't create new probes
32 // for the other file anymore. The dtrace probes have to remain stable.
33 void VM_GC_Operation::notify_gc_begin(bool full) {
34 HS_DTRACE_PROBE1(hotspot, gc__begin, full);
35 }
37 void VM_GC_Operation::notify_gc_end() {
38 HS_DTRACE_PROBE(hotspot, gc__end);
39 }
41 void VM_GC_Operation::acquire_pending_list_lock() {
42 // we may enter this with pending exception set
43 instanceRefKlass::acquire_pending_list_lock(&_pending_list_basic_lock);
44 }
47 void VM_GC_Operation::release_and_notify_pending_list_lock() {
49 instanceRefKlass::release_and_notify_pending_list_lock(&_pending_list_basic_lock);
50 }
52 // Allocations may fail in several threads at about the same time,
53 // resulting in multiple gc requests. We only want to do one of them.
54 // In case a GC locker is active and the need for a GC is already signalled,
55 // we want to skip this GC attempt altogether, without doing a futile
56 // safepoint operation.
57 bool VM_GC_Operation::skip_operation() const {
58 bool skip = (_gc_count_before != Universe::heap()->total_collections());
59 if (_full && skip) {
60 skip = (_full_gc_count_before != Universe::heap()->total_full_collections());
61 }
62 if (!skip && GC_locker::is_active_and_needs_gc()) {
63 skip = Universe::heap()->is_maximal_no_gc();
64 assert(!(skip && (_gc_cause == GCCause::_gc_locker)),
65 "GC_locker cannot be active when initiating GC");
66 }
67 return skip;
68 }
70 bool VM_GC_Operation::doit_prologue() {
71 assert(Thread::current()->is_Java_thread(), "just checking");
73 acquire_pending_list_lock();
74 // If the GC count has changed someone beat us to the collection
75 // Get the Heap_lock after the pending_list_lock.
76 Heap_lock->lock();
78 // Check invocations
79 if (skip_operation()) {
80 // skip collection
81 Heap_lock->unlock();
82 release_and_notify_pending_list_lock();
83 _prologue_succeeded = false;
84 } else {
85 _prologue_succeeded = true;
86 SharedHeap* sh = SharedHeap::heap();
87 if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = true;
88 }
89 return _prologue_succeeded;
90 }
93 void VM_GC_Operation::doit_epilogue() {
94 assert(Thread::current()->is_Java_thread(), "just checking");
95 // Release the Heap_lock first.
96 SharedHeap* sh = SharedHeap::heap();
97 if (sh != NULL) sh->_thread_holds_heap_lock_for_gc = false;
98 Heap_lock->unlock();
99 release_and_notify_pending_list_lock();
100 }
102 bool VM_GC_HeapInspection::doit_prologue() {
103 if (Universe::heap()->supports_heap_inspection()) {
104 return VM_GC_Operation::doit_prologue();
105 } else {
106 return false;
107 }
108 }
110 bool VM_GC_HeapInspection::skip_operation() const {
111 assert(Universe::heap()->supports_heap_inspection(), "huh?");
112 return false;
113 }
115 void VM_GC_HeapInspection::doit() {
116 HandleMark hm;
117 CollectedHeap* ch = Universe::heap();
118 if (_full_gc) {
119 ch->collect_as_vm_thread(GCCause::_heap_inspection);
120 } else {
121 // make the heap parsable (no need to retire TLABs)
122 ch->ensure_parsability(false);
123 }
124 HeapInspection::heap_inspection(_out, _need_prologue /* need_prologue */);
125 }
128 void VM_GenCollectForAllocation::doit() {
129 JvmtiGCForAllocationMarker jgcm;
130 notify_gc_begin(false);
132 GenCollectedHeap* gch = GenCollectedHeap::heap();
133 GCCauseSetter gccs(gch, _gc_cause);
134 _res = gch->satisfy_failed_allocation(_size, _tlab);
135 assert(gch->is_in_reserved_or_null(_res), "result not in heap");
137 if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
138 set_gc_locked();
139 }
140 notify_gc_end();
141 }
143 void VM_GenCollectFull::doit() {
144 JvmtiGCFullMarker jgcm;
145 notify_gc_begin(true);
147 GenCollectedHeap* gch = GenCollectedHeap::heap();
148 GCCauseSetter gccs(gch, _gc_cause);
149 gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);
150 notify_gc_end();
151 }
153 void VM_GenCollectForPermanentAllocation::doit() {
154 JvmtiGCForAllocationMarker jgcm;
155 notify_gc_begin(true);
156 SharedHeap* heap = (SharedHeap*)Universe::heap();
157 GCCauseSetter gccs(heap, _gc_cause);
158 switch (heap->kind()) {
159 case (CollectedHeap::GenCollectedHeap): {
160 GenCollectedHeap* gch = (GenCollectedHeap*)heap;
161 gch->do_full_collection(gch->must_clear_all_soft_refs(),
162 gch->n_gens() - 1);
163 break;
164 }
165 #ifndef SERIALGC
166 case (CollectedHeap::G1CollectedHeap): {
167 G1CollectedHeap* g1h = (G1CollectedHeap*)heap;
168 g1h->do_full_collection(_gc_cause == GCCause::_last_ditch_collection);
169 break;
170 }
171 #endif // SERIALGC
172 default:
173 ShouldNotReachHere();
174 }
175 _res = heap->perm_gen()->allocate(_size, false);
176 assert(heap->is_in_reserved_or_null(_res), "result not in heap");
177 if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
178 set_gc_locked();
179 }
180 notify_gc_end();
181 }