hotspot/src/share/vm/gc_implementation/g1/vm_operations_g1.cpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2001, 2010, 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/g1CollectedHeap.inline.hpp"
 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"
 #include "gc_implementation/shared/isGCActiveMark.hpp"
 #include "gc_implementation/g1/vm_operations_g1.hpp"
 #include "runtime/interfaceSupport.hpp"

 VM_G1CollectForAllocation::VM_G1CollectForAllocation(
                                                   unsigned int gc_count_before,
                                                   size_t word_size)
   : VM_G1OperationWithAllocRequest(gc_count_before, word_size) {
   guarantee(word_size > 0, "an allocation should always be requested");
 }

 void VM_G1CollectForAllocation::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   _result = g1h->satisfy_failed_allocation(_word_size, &_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(
                                       unsigned int   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),
     _should_initiate_conc_mark(should_initiate_conc_mark),
     _target_pause_time_ms(target_pause_time_ms),
     _full_collections_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));
   guarantee(word_size == 0 || gc_cause == GCCause::_g1_inc_collection_pause,
             "we can only request an allocation if the GC cause is for "
             "an incremental GC pause");
   _gc_cause = gc_cause;
 }

 void VM_G1IncCollectionPause::doit() {
   G1CollectedHeap* g1h = G1CollectedHeap::heap();
   assert(!_should_initiate_conc_mark ||
   ((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) ||
    (_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)),
          "only a GC locker or a System.gc() 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,
                                      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 full_collections_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.
     _full_collections_completed_before = g1h->full_collections_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();
   }

   _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,
                                       true /* expect_null_cur_alloc_region */);
   } else {
     assert(_result == NULL, "invariant");
   }
 }

 void VM_G1IncCollectionPause::doit_epilogue() {
   VM_GC_Operation::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->full_collections_completed()
     // in the _full_collections_completed_before field. We have to
     // wait until we observe that g1h->full_collections_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->full_collections_completed() <=
                                           _full_collections_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->full_collections_completed() <=
                                           _full_collections_completed_before) {
         FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
       }
     }
   }
 }

 void VM_CGC_Operation::doit() {
   gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
   TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
   TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
   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() {
   Heap_lock->lock();
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
   return true;
 }

 void VM_CGC_Operation::doit_epilogue() {
   SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
   Heap_lock->unlock();
 }
	/*
	* Copyright (c) 2001, 2010, 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/g1CollectedHeap.inline.hpp"
	#include "gc_implementation/g1/g1CollectorPolicy.hpp"
	#include "gc_implementation/g1/vm_operations_g1.hpp"
	#include "gc_implementation/shared/isGCActiveMark.hpp"
	#include "gc_implementation/g1/vm_operations_g1.hpp"
	#include "runtime/interfaceSupport.hpp"

	VM_G1CollectForAllocation::VM_G1CollectForAllocation(
	unsigned int gc_count_before,
	size_t word_size)
	: VM_G1OperationWithAllocRequest(gc_count_before, word_size) {
	guarantee(word_size > 0, "an allocation should always be requested");
	}

	void VM_G1CollectForAllocation::doit() {
	G1CollectedHeap* g1h = G1CollectedHeap::heap();
	_result = g1h->satisfy_failed_allocation(_word_size, &_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(
	unsigned int 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),
	_should_initiate_conc_mark(should_initiate_conc_mark),
	_target_pause_time_ms(target_pause_time_ms),
	_full_collections_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));
	guarantee(word_size == 0 \|\| gc_cause == GCCause::_g1_inc_collection_pause,
	"we can only request an allocation if the GC cause is for "
	"an incremental GC pause");
	_gc_cause = gc_cause;
	}

	void VM_G1IncCollectionPause::doit() {
	G1CollectedHeap* g1h = G1CollectedHeap::heap();
	assert(!_should_initiate_conc_mark \|\|
	((_gc_cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) \|\|
	(_gc_cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)),
	"only a GC locker or a System.gc() 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,
	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 full_collections_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.
	_full_collections_completed_before = g1h->full_collections_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();
	}

	_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,
	true /* expect_null_cur_alloc_region */);
	} else {
	assert(_result == NULL, "invariant");
	}
	}

	void VM_G1IncCollectionPause::doit_epilogue() {
	VM_GC_Operation::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->full_collections_completed()
	// in the _full_collections_completed_before field. We have to
	// wait until we observe that g1h->full_collections_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->full_collections_completed() <=
	_full_collections_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->full_collections_completed() <=
	_full_collections_completed_before) {
	FullGCCount_lock->wait(Mutex::_no_safepoint_check_flag);
	}
	}
	}
	}

	void VM_CGC_Operation::doit() {
	gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
	TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
	TraceTime t(_printGCMessage, PrintGC, true, gclog_or_tty);
	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() {
	Heap_lock->lock();
	SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
	return true;
	}

	void VM_CGC_Operation::doit_epilogue() {
	SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
	Heap_lock->unlock();
	}