tonyp@2472: /*
tonyp@2472:  * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
tonyp@2472:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
tonyp@2472:  *
tonyp@2472:  * This code is free software; you can redistribute it and/or modify it
tonyp@2472:  * under the terms of the GNU General Public License version 2 only, as
tonyp@2472:  * published by the Free Software Foundation.
tonyp@2472:  *
tonyp@2472:  * This code is distributed in the hope that it will be useful, but WITHOUT
tonyp@2472:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
tonyp@2472:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
tonyp@2472:  * version 2 for more details (a copy is included in the LICENSE file that
tonyp@2472:  * accompanied this code).
tonyp@2472:  *
tonyp@2472:  * You should have received a copy of the GNU General Public License version
tonyp@2472:  * 2 along with this work; if not, write to the Free Software Foundation,
tonyp@2472:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
tonyp@2472:  *
tonyp@2472:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
tonyp@2472:  * or visit www.oracle.com if you need additional information or have any
tonyp@2472:  * questions.
tonyp@2472:  *
tonyp@2472:  */
tonyp@2472: 
tonyp@2472: #include "precompiled.hpp"
tonyp@2974: #include "gc_implementation/g1/heapRegionRemSet.hpp"
tonyp@2472: #include "gc_implementation/g1/heapRegionSets.hpp"
tonyp@2472: 
tonyp@3268: // Note on the check_mt_safety() methods below:
tonyp@3268: //
tonyp@3268: // Verification of the "master" heap region sets / lists that are
tonyp@3268: // maintained by G1CollectedHeap is always done during a STW pause and
tonyp@3268: // by the VM thread at the start / end of the pause. The standard
tonyp@3268: // verification methods all assert check_mt_safety(). This is
tonyp@3268: // important as it ensures that verification is done without
tonyp@3268: // concurrent updates taking place at the same time. It follows, that,
tonyp@3268: // for the "master" heap region sets / lists, the check_mt_safety()
tonyp@3268: // method should include the VM thread / STW case.
tonyp@3268: 
tonyp@2472: //////////////////// FreeRegionList ////////////////////
tonyp@2472: 
tonyp@2472: const char* FreeRegionList::verify_region_extra(HeapRegion* hr) {
tonyp@2472:   if (hr->is_young()) {
tonyp@2472:     return "the region should not be young";
tonyp@2472:   }
tonyp@2472:   // The superclass will check that the region is empty and
tonyp@3268:   // not humongous.
tonyp@2472:   return HeapRegionLinkedList::verify_region_extra(hr);
tonyp@2472: }
tonyp@2472: 
tonyp@2472: //////////////////// MasterFreeRegionList ////////////////////
tonyp@2472: 
tonyp@2974: const char* MasterFreeRegionList::verify_region_extra(HeapRegion* hr) {
tonyp@2974:   // We should reset the RSet for parallel iteration before we add it
tonyp@2974:   // to the master free list so that it is ready when the region is
tonyp@2974:   // re-allocated.
tonyp@2974:   if (!hr->rem_set()->verify_ready_for_par_iteration()) {
tonyp@2974:     return "the region's RSet should be ready for parallel iteration";
tonyp@2974:   }
tonyp@2974:   return FreeRegionList::verify_region_extra(hr);
tonyp@2974: }
tonyp@2974: 
tonyp@2472: bool MasterFreeRegionList::check_mt_safety() {
tonyp@2472:   // Master Free List MT safety protocol:
tonyp@2472:   // (a) If we're at a safepoint, operations on the master free list
tonyp@2472:   // should be invoked by either the VM thread (which will serialize
tonyp@2472:   // them) or by the GC workers while holding the
tonyp@2472:   // FreeList_lock.
tonyp@2472:   // (b) If we're not at a safepoint, operations on the master free
tonyp@2472:   // list should be invoked while holding the Heap_lock.
tonyp@2472: 
tonyp@3268:   if (SafepointSynchronize::is_at_safepoint()) {
tonyp@3268:     guarantee(Thread::current()->is_VM_thread() ||
tonyp@3268:               FreeList_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master free list MT safety protocol "
tonyp@3268:                                 "at a safepoint"));
tonyp@3268:   } else {
tonyp@3268:     guarantee(Heap_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master free list MT safety protocol "
tonyp@3268:                                 "outside a safepoint"));
tonyp@3268:   }
tonyp@2472: 
tonyp@2472:   return FreeRegionList::check_mt_safety();
tonyp@2472: }
tonyp@2472: 
tonyp@2472: //////////////////// SecondaryFreeRegionList ////////////////////
tonyp@2472: 
tonyp@2472: bool SecondaryFreeRegionList::check_mt_safety() {
tonyp@2472:   // Secondary Free List MT safety protocol:
tonyp@2472:   // Operations on the secondary free list should always be invoked
tonyp@2472:   // while holding the SecondaryFreeList_lock.
tonyp@2472: 
tonyp@2472:   guarantee(SecondaryFreeList_lock->owned_by_self(),
tonyp@2643:             hrs_ext_msg(this, "secondary free list MT safety protocol"));
tonyp@2472: 
tonyp@2472:   return FreeRegionList::check_mt_safety();
tonyp@2472: }
tonyp@2472: 
tonyp@3268: //////////////////// OldRegionSet ////////////////////
tonyp@3268: 
tonyp@3268: const char* OldRegionSet::verify_region_extra(HeapRegion* hr) {
tonyp@3268:   if (hr->is_young()) {
tonyp@3268:     return "the region should not be young";
tonyp@3268:   }
tonyp@3268:   // The superclass will check that the region is not empty and not
tonyp@3268:   // humongous.
tonyp@3268:   return HeapRegionSet::verify_region_extra(hr);
tonyp@3268: }
tonyp@3268: 
tonyp@3268: //////////////////// MasterOldRegionSet ////////////////////
tonyp@3268: 
tonyp@3268: bool MasterOldRegionSet::check_mt_safety() {
tonyp@3268:   // Master Old Set MT safety protocol:
tonyp@3268:   // (a) If we're at a safepoint, operations on the master old set
tonyp@3268:   // should be invoked:
tonyp@3268:   // - by the VM thread (which will serialize them), or
tonyp@3268:   // - by the GC workers while holding the FreeList_lock, if we're
tonyp@3268:   //   at a safepoint for an evacuation pause (this lock is taken
tonyp@3268:   //   anyway when an GC alloc region is retired so that a new one
tonyp@3268:   //   is allocated from the free list), or
tonyp@3268:   // - by the GC workers while holding the OldSets_lock, if we're at a
tonyp@3268:   //   safepoint for a cleanup pause.
tonyp@3268:   // (b) If we're not at a safepoint, operations on the master old set
tonyp@3268:   // should be invoked while holding the Heap_lock.
tonyp@3268: 
tonyp@3268:   if (SafepointSynchronize::is_at_safepoint()) {
tonyp@3268:     guarantee(Thread::current()->is_VM_thread() ||
tonyp@3268:               _phase == HRSPhaseEvacuation && FreeList_lock->owned_by_self() ||
tonyp@3268:               _phase == HRSPhaseCleanup && OldSets_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master old set MT safety protocol "
tonyp@3268:                                 "at a safepoint"));
tonyp@3268:   } else {
tonyp@3268:     guarantee(Heap_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master old set MT safety protocol "
tonyp@3268:                                 "outside a safepoint"));
tonyp@3268:   }
tonyp@3268: 
tonyp@3268:   return OldRegionSet::check_mt_safety();
tonyp@3268: }
tonyp@3268: 
tonyp@2472: //////////////////// HumongousRegionSet ////////////////////
tonyp@2472: 
tonyp@2472: const char* HumongousRegionSet::verify_region_extra(HeapRegion* hr) {
tonyp@2472:   if (hr->is_young()) {
tonyp@2472:     return "the region should not be young";
tonyp@2472:   }
tonyp@2472:   // The superclass will check that the region is not empty and
tonyp@2472:   // humongous.
tonyp@2472:   return HeapRegionSet::verify_region_extra(hr);
tonyp@2472: }
tonyp@2472: 
tonyp@2643: //////////////////// MasterHumongousRegionSet ////////////////////
tonyp@2472: 
tonyp@2472: bool MasterHumongousRegionSet::check_mt_safety() {
tonyp@2472:   // Master Humongous Set MT safety protocol:
tonyp@2472:   // (a) If we're at a safepoint, operations on the master humongous
tonyp@2472:   // set should be invoked by either the VM thread (which will
tonyp@2472:   // serialize them) or by the GC workers while holding the
tonyp@2472:   // OldSets_lock.
tonyp@2472:   // (b) If we're not at a safepoint, operations on the master
tonyp@2472:   // humongous set should be invoked while holding the Heap_lock.
tonyp@2472: 
tonyp@3268:   if (SafepointSynchronize::is_at_safepoint()) {
tonyp@3268:     guarantee(Thread::current()->is_VM_thread() ||
tonyp@3268:               OldSets_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master humongous set MT safety protocol "
tonyp@3268:                                 "at a safepoint"));
tonyp@3268:   } else {
tonyp@3268:     guarantee(Heap_lock->owned_by_self(),
tonyp@3268:               hrs_ext_msg(this, "master humongous set MT safety protocol "
tonyp@3268:                                 "outside a safepoint"));
tonyp@3268:   }
tonyp@3268: 
tonyp@2472:   return HumongousRegionSet::check_mt_safety();
tonyp@2472: }