Fri, 09 Sep 2011 05:20:58 -0400
7087717: G1: make the G1PrintRegionLivenessInfo parameter diagnostic
Reviewed-by: brutisso, ysr
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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).
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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.
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23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
27 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
28 #include "gc_implementation/g1/vm_operations_g1.hpp"
29 #include "gc_implementation/shared/isGCActiveMark.hpp"
30 #include "gc_implementation/g1/vm_operations_g1.hpp"
31 #include "runtime/interfaceSupport.hpp"
33 VM_G1CollectForAllocation::VM_G1CollectForAllocation(
34 unsigned int gc_count_before,
35 size_t word_size)
36 : VM_G1OperationWithAllocRequest(gc_count_before, word_size) {
37 guarantee(word_size > 0, "an allocation should always be requested");
38 }
40 void VM_G1CollectForAllocation::doit() {
41 G1CollectedHeap* g1h = G1CollectedHeap::heap();
42 _result = g1h->satisfy_failed_allocation(_word_size, &_pause_succeeded);
43 assert(_result == NULL || _pause_succeeded,
44 "if we get back a result, the pause should have succeeded");
45 }
47 void VM_G1CollectFull::doit() {
48 G1CollectedHeap* g1h = G1CollectedHeap::heap();
49 GCCauseSetter x(g1h, _gc_cause);
50 g1h->do_full_collection(false /* clear_all_soft_refs */);
51 }
53 VM_G1IncCollectionPause::VM_G1IncCollectionPause(
54 unsigned int gc_count_before,
55 size_t word_size,
56 bool should_initiate_conc_mark,
57 double target_pause_time_ms,
58 GCCause::Cause gc_cause)
59 : VM_G1OperationWithAllocRequest(gc_count_before, word_size),
60 _should_initiate_conc_mark(should_initiate_conc_mark),
61 _target_pause_time_ms(target_pause_time_ms),
62 _full_collections_completed_before(0) {
63 guarantee(target_pause_time_ms > 0.0,
64 err_msg("target_pause_time_ms = %1.6lf should be positive",
65 target_pause_time_ms));
66 guarantee(word_size == 0 || gc_cause == GCCause::_g1_inc_collection_pause,
67 "we can only request an allocation if the GC cause is for "
68 "an incremental GC pause");
69 _gc_cause = gc_cause;
70 }
72 void VM_G1IncCollectionPause::doit() {
73 G1CollectedHeap* g1h = G1CollectedHeap::heap();
74 assert(!_should_initiate_conc_mark ||
75 ((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
76 (_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)),
77 "only a GC locker or a System.gc() induced GC should start a cycle");
79 if (_word_size > 0) {
80 // An allocation has been requested. So, try to do that first.
81 _result = g1h->attempt_allocation_at_safepoint(_word_size,
82 false /* expect_null_cur_alloc_region */);
83 if (_result != NULL) {
84 // If we can successfully allocate before we actually do the
85 // pause then we will consider this pause successful.
86 _pause_succeeded = true;
87 return;
88 }
89 }
91 GCCauseSetter x(g1h, _gc_cause);
92 if (_should_initiate_conc_mark) {
93 // It's safer to read full_collections_completed() here, given
94 // that noone else will be updating it concurrently. Since we'll
95 // only need it if we're initiating a marking cycle, no point in
96 // setting it earlier.
97 _full_collections_completed_before = g1h->full_collections_completed();
99 // At this point we are supposed to start a concurrent cycle. We
100 // will do so if one is not already in progress.
101 bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);
103 // The above routine returns true if we were able to force the
104 // next GC pause to be an initial mark; it returns false if a
105 // marking cycle is already in progress.
106 //
107 // If a marking cycle is already in progress just return and skip
108 // the pause - the requesting thread should block in doit_epilogue
109 // until the marking cycle is complete.
110 if (!res) {
111 assert(_word_size == 0, "ExplicitGCInvokesConcurrent shouldn't be allocating");
112 return;
113 }
114 }
116 _pause_succeeded =
117 g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
118 if (_pause_succeeded && _word_size > 0) {
119 // An allocation had been requested.
120 _result = g1h->attempt_allocation_at_safepoint(_word_size,
121 true /* expect_null_cur_alloc_region */);
122 } else {
123 assert(_result == NULL, "invariant");
124 }
125 }
127 void VM_G1IncCollectionPause::doit_epilogue() {
128 VM_GC_Operation::doit_epilogue();
130 // If the pause was initiated by a System.gc() and
131 // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
132 // that just started (or maybe one that was already in progress) to
133 // finish.
134 if (_gc_cause == GCCause::_java_lang_system_gc &&
135 _should_initiate_conc_mark) {
136 assert(ExplicitGCInvokesConcurrent,
137 "the only way to be here is if ExplicitGCInvokesConcurrent is set");
139 G1CollectedHeap* g1h = G1CollectedHeap::heap();
141 // In the doit() method we saved g1h->full_collections_completed()
142 // in the _full_collections_completed_before field. We have to
143 // wait until we observe that g1h->full_collections_completed()
144 // has increased by at least one. This can happen if a) we started
145 // a cycle and it completes, b) a cycle already in progress
146 // completes, or c) a Full GC happens.
148 // If the condition has already been reached, there's no point in
149 // actually taking the lock and doing the wait.
150 if (g1h->full_collections_completed() <=
151 _full_collections_completed_before) {
152 // The following is largely copied from CMS
154 Thread* thr = Thread::current();
155 assert(thr->is_Java_thread(), "invariant");
156 JavaThread* jt = (JavaThread*)thr;
157 ThreadToNativeFromVM native(jt);
159 MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
160 while (g1h->full_collections_completed() <=
161 _full_collections_completed_before) {
162 FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
163 }
164 }
165 }
166 }
168 void VM_CGC_Operation::doit() {
169 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
170 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
171 TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
172 SharedHeap* sh = SharedHeap::heap();
173 // This could go away if CollectedHeap gave access to _gc_is_active...
174 if (sh != NULL) {
175 IsGCActiveMark x;
176 _cl->do_void();
177 } else {
178 _cl->do_void();
179 }
180 }
182 bool VM_CGC_Operation::doit_prologue() {
183 Heap_lock->lock();
184 SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
185 return true;
186 }
188 void VM_CGC_Operation::doit_epilogue() {
189 SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
190 Heap_lock->unlock();
191 }