src/share/vm/gc_implementation/g1/vm_operations_g1.cpp - platform/external/jetbrains/jdk8u_hotspot - Git at Google

 /*
  * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */

 #include "precompiled.hpp"
 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/g1Log.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"
 #include "gc_implementation/shared/gcTimer.hpp"
 #include "gc_implementation/shared/gcTraceTime.hpp"
 #include "gc_implementation/shared/isGCActiveMark.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"
 #include "runtime/interfaceSupport.hpp"

 VM_G1CollectForAllocation::VM_G1CollectForAllocation(uint gc_count_before,
                                                      size_t word_size)
   : VM_G1OperationWithAllocRequest(gc_count_before, word_size,
                                    GCCause::_allocation_failure) {
   guarantee(word_size != 0, "An allocation should always be requested with this operation.");
 }

 void VM_G1CollectForAllocation::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   GCCauseSetter x(g1h, _gc_cause);

   _result = g1h->satisfy_failed_allocation(_word_size, allocation_context(), &_pause_succeeded);
   assert(_result == NULL || _pause_succeeded,
          "if we get back a result, the pause should have succeeded");
 }

 void VM_G1CollectFull::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   GCCauseSetter x(g1h, _gc_cause);
   g1h->do_full_collection(false /* clear_all_soft_refs */);
 }

 VM_G1IncCollectionPause::VM_G1IncCollectionPause(uint           gc_count_before,
                                                  size_t         word_size,
                                                  bool           should_initiate_conc_mark,
                                                  double         target_pause_time_ms,
                                                  GCCause::Cause gc_cause)
   : VM_G1OperationWithAllocRequest(gc_count_before, word_size, gc_cause),
     _should_initiate_conc_mark(should_initiate_conc_mark),
     _target_pause_time_ms(target_pause_time_ms),
     _should_retry_gc(false),
     _old_marking_cycles_completed_before(0) {
   guarantee(target_pause_time_ms > 0.0,
             err_msg("target_pause_time_ms = %1.6lf should be positive",
                     target_pause_time_ms));
   _gc_cause = gc_cause;
 }

 bool VM_G1IncCollectionPause::doit_prologue() {
   bool res = VM_G1OperationWithAllocRequest::doit_prologue();
   if (!res) {
     if (_should_initiate_conc_mark) {
       // The prologue can fail for a couple of reasons. The first is that another GC
       // got scheduled and prevented the scheduling of the initial mark GC. The
       // second is that the GC locker may be active and the heap can't be expanded.
       // In both cases we want to retry the GC so that the initial mark pause is
       // actually scheduled. In the second case, however, we should stall until
       // until the GC locker is no longer active and then retry the initial mark GC.
       _should_retry_gc = true;
     }
   }
   return res;
 }

 void VM_G1IncCollectionPause::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   assert(!_should_initiate_conc_mark || g1h->should_do_concurrent_full_gc(_gc_cause),
       "only a GC locker, a System.gc(), stats update, whitebox, or a hum allocation induced GC should start a cycle");

   if (_word_size > 0) {
     // An allocation has been requested. So, try to do that first.
     _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
                                      false /* expect_null_cur_alloc_region */);
     if (_result != NULL) {
       // If we can successfully allocate before we actually do the
       // pause then we will consider this pause successful.
       _pause_succeeded = true;
       return;
     }
   }

   GCCauseSetter x(g1h, _gc_cause);
   if (_should_initiate_conc_mark) {
     // It's safer to read old_marking_cycles_completed() here, given
     // that noone else will be updating it concurrently. Since we'll
     // only need it if we're initiating a marking cycle, no point in
     // setting it earlier.
     _old_marking_cycles_completed_before = g1h->old_marking_cycles_completed();

     // At this point we are supposed to start a concurrent cycle. We
     // will do so if one is not already in progress.
     bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);

     // The above routine returns true if we were able to force the
     // next GC pause to be an initial mark; it returns false if a
     // marking cycle is already in progress.
     //
     // If a marking cycle is already in progress just return and skip the
     // pause below - if the reason for requesting this initial mark pause
     // was due to a System.gc() then the requesting thread should block in
     // doit_epilogue() until the marking cycle is complete.
     //
     // If this initial mark pause was requested as part of a humongous
     // allocation then we know that the marking cycle must just have
     // been started by another thread (possibly also allocating a humongous
     // object) as there was no active marking cycle when the requesting
     // thread checked before calling collect() in
     // attempt_allocation_humongous(). Retrying the GC, in this case,
     // will cause the requesting thread to spin inside collect() until the
     // just started marking cycle is complete - which may be a while. So
     // we do NOT retry the GC.
     if (!res) {
       assert(_word_size == 0, "Concurrent Full GC/Humongous Object IM shouldn't be allocating");
       if (_gc_cause != GCCause::_g1_humongous_allocation) {
         _should_retry_gc = true;
       }
       return;
     }
   }

   _pause_succeeded =
     g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
   if (_pause_succeeded && _word_size > 0) {
     // An allocation had been requested.
     _result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
                                       true /* expect_null_cur_alloc_region */);
   } else {
     assert(_result == NULL, "invariant");
     if (!_pause_succeeded) {
       // Another possible reason reason for the pause to not be successful
       // is that, again, the GC locker is active (and has become active
       // since the prologue was executed). In this case we should retry
       // the pause after waiting for the GC locker to become inactive.
       _should_retry_gc = true;
     }
   }
 }

 void VM_G1IncCollectionPause::doit_epilogue() {
   VM_G1OperationWithAllocRequest::doit_epilogue();

   // If the pause was initiated by a System.gc() and
   // +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
   // that just started (or maybe one that was already in progress) to
   // finish.
   if (_gc_cause == GCCause::_java_lang_system_gc &&
       _should_initiate_conc_mark) {
     assert(ExplicitGCInvokesConcurrent,
            "the only way to be here is if ExplicitGCInvokesConcurrent is set");

     G1CollectedHeap* g1h = G1CollectedHeap::heap();

     // In the doit() method we saved g1h->old_marking_cycles_completed()
     // in the _old_marking_cycles_completed_before field. We have to
     // wait until we observe that g1h->old_marking_cycles_completed()
     // has increased by at least one. This can happen if a) we started
     // a cycle and it completes, b) a cycle already in progress
     // completes, or c) a Full GC happens.

     // If the condition has already been reached, there's no point in
     // actually taking the lock and doing the wait.
     if (g1h->old_marking_cycles_completed() <=
                                           _old_marking_cycles_completed_before) {
       // The following is largely copied from CMS

       Thread* thr = Thread::current();
       assert(thr->is_Java_thread(), "invariant");
       JavaThread* jt = (JavaThread*)thr;
       ThreadToNativeFromVM native(jt);

       MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
       while (g1h->old_marking_cycles_completed() <=
                                           _old_marking_cycles_completed_before) {
         FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
       }
     }
   }
 }

 void VM_CGC_Operation::acquire_pending_list_lock() {
   assert(_needs_pll, "don't call this otherwise");
   // The caller may block while communicating
   // with the SLT thread in order to acquire/release the PLL.
   SurrogateLockerThread* slt = ConcurrentMarkThread::slt();
   if (slt != NULL) {
     slt->manipulatePLL(SurrogateLockerThread::acquirePLL);
   } else {
     SurrogateLockerThread::report_missing_slt();
   }
 }

 void VM_CGC_Operation::release_and_notify_pending_list_lock() {
   assert(_needs_pll, "don't call this otherwise");
   // The caller may block while communicating
   // with the SLT thread in order to acquire/release the PLL.
   ConcurrentMarkThread::slt()->
     manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
 }

 void VM_CGC_Operation::doit() {
   TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
   GCTraceTime t(_printGCMessage, G1Log::fine(), true, G1CollectedHeap::heap()->gc_timer_cm(), G1CollectedHeap::heap()->concurrent_mark()->concurrent_gc_id());
   SharedHeap* sh = SharedHeap::heap();
   // This could go away if CollectedHeap gave access to _gc_is_active...
   if (sh != NULL) {
     IsGCActiveMark x;
     _cl->do_void();
   } else {
     _cl->do_void();
   }
 }

 bool VM_CGC_Operation::doit_prologue() {
   // Note the relative order of the locks must match that in
   // VM_GC_Operation::doit_prologue() or deadlocks can occur
   if (_needs_pll) {
     acquire_pending_list_lock();
   }

   Heap_lock->lock();
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
   return true;
 }

 void VM_CGC_Operation::doit_epilogue() {
   // Note the relative order of the unlocks must match that in
   // VM_GC_Operation::doit_epilogue()
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
   Heap_lock->unlock();
   if (_needs_pll) {
     release_and_notify_pending_list_lock();
   }
 }
	/*
	* Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*
	*/

	#include "precompiled.hpp"
	#include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
	#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
	#include "gc_implementation/g1/g1CollectorPolicy.hpp"
	#include "gc_implementation/g1/g1Log.hpp"
	#include "gc_implementation/g1/vm_operations_g1.hpp"
	#include "gc_implementation/shared/gcTimer.hpp"
	#include "gc_implementation/shared/gcTraceTime.hpp"
	#include "gc_implementation/shared/isGCActiveMark.hpp"
	#include "gc_implementation/g1/vm_operations_g1.hpp"
	#include "runtime/interfaceSupport.hpp"

	VM_G1CollectForAllocation::VM_G1CollectForAllocation(uint gc_count_before,
	size_t word_size)
	: VM_G1OperationWithAllocRequest(gc_count_before, word_size,
	GCCause::_allocation_failure) {
	guarantee(word_size != 0, "An allocation should always be requested with this operation.");
	}

	void VM_G1CollectForAllocation::doit() {
	G1CollectedHeap* g1h = G1CollectedHeap::heap();
	GCCauseSetter x(g1h, _gc_cause);

	_result = g1h->satisfy_failed_allocation(_word_size, allocation_context(), &_pause_succeeded);
	assert(_result == NULL \|\| _pause_succeeded,
	"if we get back a result, the pause should have succeeded");
	}

	void VM_G1CollectFull::doit() {
	G1CollectedHeap* g1h = G1CollectedHeap::heap();
	GCCauseSetter x(g1h, _gc_cause);
	g1h->do_full_collection(false /* clear_all_soft_refs */);
	}

	VM_G1IncCollectionPause::VM_G1IncCollectionPause(uint gc_count_before,
	size_t word_size,
	bool should_initiate_conc_mark,
	double target_pause_time_ms,
	GCCause::Cause gc_cause)
	: VM_G1OperationWithAllocRequest(gc_count_before, word_size, gc_cause),
	_should_initiate_conc_mark(should_initiate_conc_mark),
	_target_pause_time_ms(target_pause_time_ms),
	_should_retry_gc(false),
	_old_marking_cycles_completed_before(0) {
	guarantee(target_pause_time_ms > 0.0,
	err_msg("target_pause_time_ms = %1.6lf should be positive",
	target_pause_time_ms));
	_gc_cause = gc_cause;
	}

	bool VM_G1IncCollectionPause::doit_prologue() {
	bool res = VM_G1OperationWithAllocRequest::doit_prologue();
	if (!res) {
	if (_should_initiate_conc_mark) {
	// The prologue can fail for a couple of reasons. The first is that another GC
	// got scheduled and prevented the scheduling of the initial mark GC. The
	// second is that the GC locker may be active and the heap can't be expanded.
	// In both cases we want to retry the GC so that the initial mark pause is
	// actually scheduled. In the second case, however, we should stall until
	// until the GC locker is no longer active and then retry the initial mark GC.
	_should_retry_gc = true;
	}
	}
	return res;
	}

	void VM_G1IncCollectionPause::doit() {
	G1CollectedHeap* g1h = G1CollectedHeap::heap();
	assert(!_should_initiate_conc_mark \|\| g1h->should_do_concurrent_full_gc(_gc_cause),
	"only a GC locker, a System.gc(), stats update, whitebox, or a hum allocation induced GC should start a cycle");

	if (_word_size > 0) {
	// An allocation has been requested. So, try to do that first.
	_result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
	false /* expect_null_cur_alloc_region */);
	if (_result != NULL) {
	// If we can successfully allocate before we actually do the
	// pause then we will consider this pause successful.
	_pause_succeeded = true;
	return;
	}
	}

	GCCauseSetter x(g1h, _gc_cause);
	if (_should_initiate_conc_mark) {
	// It's safer to read old_marking_cycles_completed() here, given
	// that noone else will be updating it concurrently. Since we'll
	// only need it if we're initiating a marking cycle, no point in
	// setting it earlier.
	_old_marking_cycles_completed_before = g1h->old_marking_cycles_completed();

	// At this point we are supposed to start a concurrent cycle. We
	// will do so if one is not already in progress.
	bool res = g1h->g1_policy()->force_initial_mark_if_outside_cycle(_gc_cause);

	// The above routine returns true if we were able to force the
	// next GC pause to be an initial mark; it returns false if a
	// marking cycle is already in progress.
	//
	// If a marking cycle is already in progress just return and skip the
	// pause below - if the reason for requesting this initial mark pause
	// was due to a System.gc() then the requesting thread should block in
	// doit_epilogue() until the marking cycle is complete.
	//
	// If this initial mark pause was requested as part of a humongous
	// allocation then we know that the marking cycle must just have
	// been started by another thread (possibly also allocating a humongous
	// object) as there was no active marking cycle when the requesting
	// thread checked before calling collect() in
	// attempt_allocation_humongous(). Retrying the GC, in this case,
	// will cause the requesting thread to spin inside collect() until the
	// just started marking cycle is complete - which may be a while. So
	// we do NOT retry the GC.
	if (!res) {
	assert(_word_size == 0, "Concurrent Full GC/Humongous Object IM shouldn't be allocating");
	if (_gc_cause != GCCause::_g1_humongous_allocation) {
	_should_retry_gc = true;
	}
	return;
	}
	}

	_pause_succeeded =
	g1h->do_collection_pause_at_safepoint(_target_pause_time_ms);
	if (_pause_succeeded && _word_size > 0) {
	// An allocation had been requested.
	_result = g1h->attempt_allocation_at_safepoint(_word_size, allocation_context(),
	true /* expect_null_cur_alloc_region */);
	} else {
	assert(_result == NULL, "invariant");
	if (!_pause_succeeded) {
	// Another possible reason reason for the pause to not be successful
	// is that, again, the GC locker is active (and has become active
	// since the prologue was executed). In this case we should retry
	// the pause after waiting for the GC locker to become inactive.
	_should_retry_gc = true;
	}
	}
	}

	void VM_G1IncCollectionPause::doit_epilogue() {
	VM_G1OperationWithAllocRequest::doit_epilogue();

	// If the pause was initiated by a System.gc() and
	// +ExplicitGCInvokesConcurrent, we have to wait here for the cycle
	// that just started (or maybe one that was already in progress) to
	// finish.
	if (_gc_cause == GCCause::_java_lang_system_gc &&
	_should_initiate_conc_mark) {
	assert(ExplicitGCInvokesConcurrent,
	"the only way to be here is if ExplicitGCInvokesConcurrent is set");

	G1CollectedHeap* g1h = G1CollectedHeap::heap();

	// In the doit() method we saved g1h->old_marking_cycles_completed()
	// in the _old_marking_cycles_completed_before field. We have to
	// wait until we observe that g1h->old_marking_cycles_completed()
	// has increased by at least one. This can happen if a) we started
	// a cycle and it completes, b) a cycle already in progress
	// completes, or c) a Full GC happens.

	// If the condition has already been reached, there's no point in
	// actually taking the lock and doing the wait.
	if (g1h->old_marking_cycles_completed() <=
	_old_marking_cycles_completed_before) {
	// The following is largely copied from CMS

	Thread* thr = Thread::current();
	assert(thr->is_Java_thread(), "invariant");
	JavaThread* jt = (JavaThread*)thr;
	ThreadToNativeFromVM native(jt);

	MutexLockerEx x(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
	while (g1h->old_marking_cycles_completed() <=
	_old_marking_cycles_completed_before) {
	FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
	}
	}
	}
	}

	void VM_CGC_Operation::acquire_pending_list_lock() {
	assert(_needs_pll, "don't call this otherwise");
	// The caller may block while communicating
	// with the SLT thread in order to acquire/release the PLL.
	SurrogateLockerThread* slt = ConcurrentMarkThread::slt();
	if (slt != NULL) {
	slt->manipulatePLL(SurrogateLockerThread::acquirePLL);
	} else {
	SurrogateLockerThread::report_missing_slt();
	}
	}

	void VM_CGC_Operation::release_and_notify_pending_list_lock() {
	assert(_needs_pll, "don't call this otherwise");
	// The caller may block while communicating
	// with the SLT thread in order to acquire/release the PLL.
	ConcurrentMarkThread::slt()->
	manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL);
	}

	void VM_CGC_Operation::doit() {
	TraceCPUTime tcpu(G1Log::finer(), true, gclog_or_tty);
	GCTraceTime t(_printGCMessage, G1Log::fine(), true, G1CollectedHeap::heap()->gc_timer_cm(), G1CollectedHeap::heap()->concurrent_mark()->concurrent_gc_id());
	SharedHeap* sh = SharedHeap::heap();
	// This could go away if CollectedHeap gave access to _gc_is_active...
	if (sh != NULL) {
	IsGCActiveMark x;
	_cl->do_void();
	} else {
	_cl->do_void();
	}
	}

	bool VM_CGC_Operation::doit_prologue() {
	// Note the relative order of the locks must match that in
	// VM_GC_Operation::doit_prologue() or deadlocks can occur
	if (_needs_pll) {
	acquire_pending_list_lock();
	}

	Heap_lock->lock();
	SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
	return true;
	}

	void VM_CGC_Operation::doit_epilogue() {
	// Note the relative order of the unlocks must match that in
	// VM_GC_Operation::doit_epilogue()
	SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
	Heap_lock->unlock();
	if (_needs_pll) {
	release_and_notify_pending_list_lock();
	}
	}