rev 53920 : imported patch 8218880-g1-crashes-periodic-gc-gclocker

   1 /*
   2  * Copyright (c) 2001, 2018, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
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  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc/g1/g1CollectedHeap.inline.hpp"
  27 #include "gc/g1/g1ConcurrentMarkThread.inline.hpp"
  28 #include "gc/g1/g1Policy.hpp"
  29 #include "gc/g1/g1VMOperations.hpp"
  30 #include "gc/shared/gcId.hpp"
  31 #include "gc/shared/gcTimer.hpp"
  32 #include "gc/shared/gcTraceTime.inline.hpp"
  33 #include "gc/shared/isGCActiveMark.hpp"
  34 #include "runtime/interfaceSupport.inline.hpp"
  35 
  36 void VM_G1CollectFull::doit() {
  37   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  38   GCCauseSetter x(g1h, _gc_cause);
  39   g1h->do_full_collection(false /* clear_all_soft_refs */);
  40 }
  41 
  42 VM_G1CollectForAllocation::VM_G1CollectForAllocation(size_t         word_size,
  43                                                      uint           gc_count_before,
  44                                                      GCCause::Cause gc_cause,
  45                                                      bool           should_initiate_conc_mark,
  46                                                      double         target_pause_time_ms) :
  47   VM_CollectForAllocation(word_size, gc_count_before, gc_cause),
  48   _pause_succeeded(false),
  49   _should_initiate_conc_mark(should_initiate_conc_mark),
  50   _should_retry_gc(false),
  51   _target_pause_time_ms(target_pause_time_ms),
  52   _old_marking_cycles_completed_before(0) {
  53 
  54   guarantee(target_pause_time_ms > 0.0,
  55             "target_pause_time_ms = %1.6lf should be positive",
  56             target_pause_time_ms);
  57   _gc_cause = gc_cause;
  58 }
  59 
  60 bool VM_G1CollectForAllocation::doit_prologue() {
  61   bool res = VM_CollectForAllocation::doit_prologue();
  62   if (!res) {
  63     if (_should_initiate_conc_mark) {
  64       // The prologue can fail for a couple of reasons. The first is that another GC
  65       // got scheduled and prevented the scheduling of the initial mark GC. The
  66       // second is that the GC locker may be active and the heap can't be expanded.
  67       // In both cases we want to retry the GC so that the initial mark pause is
  68       // actually scheduled. In the second case, however, we should stall until
  69       // until the GC locker is no longer active and then retry the initial mark GC.
  70       _should_retry_gc = true;
  71     }
  72   }
  73   return res;
  74 }
  75 
  76 void VM_G1CollectForAllocation::doit() {
  77   G1CollectedHeap* g1h = G1CollectedHeap::heap();
  78   assert(!_should_initiate_conc_mark || g1h->should_do_concurrent_full_gc(_gc_cause),
  79       "only a GC locker, a System.gc(), stats update, whitebox, or a hum allocation induced GC should start a cycle");
  80 
  81   if (_word_size > 0) {
  82     // An allocation has been requested. So, try to do that first.
  83     _result = g1h->attempt_allocation_at_safepoint(_word_size,
  84                                                    false /* expect_null_cur_alloc_region */);
  85     if (_result != NULL) {
  86       // If we can successfully allocate before we actually do the
  87       // pause then we will consider this pause successful.
  88       _pause_succeeded = true;
  89       return;
  90     }
  91   }
  92 
  93   GCCauseSetter x(g1h, _gc_cause);
  94   if (_should_initiate_conc_mark) {
  95     // It's safer to read old_marking_cycles_completed() here, given
  96     // that noone else will be updating it concurrently. Since we'll
  97     // only need it if we're initiating a marking cycle, no point in
  98     // setting it earlier.
  99     _old_marking_cycles_completed_before = g1h->old_marking_cycles_completed();
 100 
 101     // At this point we are supposed to start a concurrent cycle. We
 102     // will do so if one is not already in progress.
 103     bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);
 104 
 105     // The above routine returns true if we were able to force the
 106     // next GC pause to be an initial mark; it returns false if a
 107     // marking cycle is already in progress.
 108     //
 109     // If a marking cycle is already in progress just return and skip the
 110     // pause below - if the reason for requesting this initial mark pause
 111     // was due to a System.gc() then the requesting thread should block in
 112     // doit_epilogue() until the marking cycle is complete.
 113     //
 114     // If this initial mark pause was requested as part of a humongous
 115     // allocation then we know that the marking cycle must just have
 116     // been started by another thread (possibly also allocating a humongous
 117     // object) as there was no active marking cycle when the requesting
 118     // thread checked before calling collect() in
 119     // attempt_allocation_humongous(). Retrying the GC, in this case,
 120     // will cause the requesting thread to spin inside collect() until the
 121     // just started marking cycle is complete - which may be a while. So
 122     // we do NOT retry the GC.
 123     if (!res) {
 124       assert(_word_size == 0, "Concurrent Full GC/Humongous Object IM shouldn't be allocating");
 125       if (_gc_cause != GCCause::_g1_humongous_allocation) {
 126         _should_retry_gc = true;
 127       }
 128       return;
 129     }
 130   }
 131 
 132   // Try a partial collection of some kind.
 133   _pause_succeeded = g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
 134 
 135   if (_pause_succeeded) {
 136     if (_word_size > 0) {
 137       // An allocation had been requested. Do it, eventually trying a stronger
 138       // kind of GC.
 139       _result = g1h->satisfy_failed_allocation(_word_size, &_pause_succeeded);
 140     } else {
 141       bool should_upgrade_to_full = g1h->should_upgrade_to_full_gc(_gc_cause);
 142 
 143       if (should_upgrade_to_full) {
 144         // There has been a request to perform a GC to free some space. We have no
 145         // information on how much memory has been asked for. In case there are
 146         // absolutely no regions left to allocate into, do a maximally compacting full GC.
 147         log_info(gc, ergo)("Attempting maximally compacting collection");
 148         _pause_succeeded = g1h->do_full_collection(false, /* explicit gc */
 149                                                    true   /* clear_all_soft_refs */);
 150       }
 151     }
 152     guarantee(_pause_succeeded, "Elevated collections during the safepoint must always succeed.");
 153   } else {
 154     assert(_result == NULL, "invariant");
 155     // The only reason for the pause to not be successful is that, the GC locker is
 156     // active (or has become active since the prologue was executed). In this case
 157     // we should retry the pause after waiting for the GC locker to become inactive.
 158     _should_retry_gc = true;
 159   }
 160 }
 161 
 162 void VM_G1CollectForAllocation::doit_epilogue() {
 163   VM_CollectForAllocation::doit_epilogue();
 164 
 165   // If the pause was initiated by a System.gc() and
 166   // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
 167   // that just started (or maybe one that was already in progress) to
 168   // finish.
 169   if (GCCause::is_user_requested_gc(_gc_cause) &&
 170       _should_initiate_conc_mark) {
 171     assert(ExplicitGCInvokesConcurrent,
 172            "the only way to be here is if ExplicitGCInvokesConcurrent is set");
 173 
 174     G1CollectedHeap* g1h = G1CollectedHeap::heap();
 175 
 176     // In the doit() method we saved g1h->old_marking_cycles_completed()
 177     // in the _old_marking_cycles_completed_before field. We have to
 178     // wait until we observe that g1h->old_marking_cycles_completed()
 179     // has increased by at least one. This can happen if a) we started
 180     // a cycle and it completes, b) a cycle already in progress
 181     // completes, or c) a Full GC happens.
 182 
 183     // If the condition has already been reached, there's no point in
 184     // actually taking the lock and doing the wait.
 185     if (g1h->old_marking_cycles_completed() <=
 186                                           _old_marking_cycles_completed_before) {
 187       // The following is largely copied from CMS
 188 
 189       Thread* thr = Thread::current();
 190       assert(thr->is_Java_thread(), "invariant");
 191       JavaThread* jt = (JavaThread*)thr;
 192       ThreadToNativeFromVM native(jt);
 193 
 194       MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
 195       while (g1h->old_marking_cycles_completed() <=
 196                                           _old_marking_cycles_completed_before) {
 197         FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
 198       }
 199     }
 200   }
 201 }
 202 
 203 void VM_G1Concurrent::doit() {
 204   GCIdMark gc_id_mark(_gc_id);
 205   GCTraceCPUTime tcpu;
 206   G1CollectedHeap* g1h = G1CollectedHeap::heap();
 207   GCTraceTime(Info, gc) t(_message, g1h->concurrent_mark()->gc_timer_cm(), GCCause::_no_gc, true);
 208   TraceCollectorStats tcs(g1h->g1mm()->conc_collection_counters());
 209   SvcGCMarker sgcm(SvcGCMarker::CONCURRENT);
 210   IsGCActiveMark x;
 211   _cl->do_void();
 212 }
 213 
 214 bool VM_G1Concurrent::doit_prologue() {
 215   Heap_lock->lock();
 216   return true;
 217 }
 218 
 219 void VM_G1Concurrent::doit_epilogue() {
 220   if (Universe::has_reference_pending_list()) {
 221     Heap_lock->notify_all();
 222   }
 223   Heap_lock->unlock();
 224 }
--- EOF ---