1 /* 2 * Copyright (c) 2014, 2015, 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. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "gc_implementation/g1/g1Allocator.hpp" 27 #include "gc_implementation/g1/g1CollectedHeap.hpp" 28 #include "gc_implementation/g1/g1CollectorPolicy.hpp" 29 #include "gc_implementation/g1/heapRegion.inline.hpp" 30 #include "gc_implementation/g1/heapRegionSet.inline.hpp" 31 32 void G1DefaultAllocator::init_mutator_alloc_region() { 33 assert(_mutator_alloc_region.get() == NULL, "pre-condition"); 34 _mutator_alloc_region.init(); 35 } 36 37 void G1DefaultAllocator::release_mutator_alloc_region() { 38 _mutator_alloc_region.release(); 39 assert(_mutator_alloc_region.get() == NULL, "post-condition"); 40 } 41 42 void G1Allocator::reuse_retained_old_region(EvacuationInfo& evacuation_info, 43 OldGCAllocRegion* old, 44 HeapRegion** retained_old) { 45 HeapRegion* retained_region = *retained_old; 46 *retained_old = NULL; 47 48 // We will discard the current GC alloc region if: 49 // a) it's in the collection set (it can happen!), 50 // b) it's already full (no point in using it), 51 // c) it's empty (this means that it was emptied during 52 // a cleanup and it should be on the free list now), or 53 // d) it's humongous (this means that it was emptied 54 // during a cleanup and was added to the free list, but 55 // has been subsequently used to allocate a humongous 56 // object that may be less than the region size). 57 if (retained_region != NULL && 58 !retained_region->in_collection_set() && 59 !(retained_region->top() == retained_region->end()) && 60 !retained_region->is_empty() && 61 !retained_region->is_humongous()) { 62 retained_region->record_timestamp(); 63 // The retained region was added to the old region set when it was 64 // retired. We have to remove it now, since we don't allow regions 65 // we allocate to in the region sets. We'll re-add it later, when 66 // it's retired again. 67 _g1h->_old_set.remove(retained_region); 68 bool during_im = _g1h->g1_policy()->during_initial_mark_pause(); 69 retained_region->note_start_of_copying(during_im); 70 old->set(retained_region); 71 _g1h->_hr_printer.reuse(retained_region); 72 evacuation_info.set_alloc_regions_used_before(retained_region->used()); 73 } 74 } 75 76 void G1DefaultAllocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) { 77 assert_at_safepoint(true /* should_be_vm_thread */); 78 79 _survivor_gc_alloc_region.init(); 80 _old_gc_alloc_region.init(); 81 reuse_retained_old_region(evacuation_info, 82 &_old_gc_alloc_region, 83 &_retained_old_gc_alloc_region); 84 } 85 86 void G1DefaultAllocator::release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) { 87 AllocationContext_t context = AllocationContext::current(); 88 evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() + 89 old_gc_alloc_region(context)->count()); 90 survivor_gc_alloc_region(context)->release(); 91 // If we have an old GC alloc region to release, we'll save it in 92 // _retained_old_gc_alloc_region. If we don't 93 // _retained_old_gc_alloc_region will become NULL. This is what we 94 // want either way so no reason to check explicitly for either 95 // condition. 96 _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release(); 97 if (_retained_old_gc_alloc_region != NULL) { 98 _retained_old_gc_alloc_region->record_retained_region(); 99 } 100 101 if (ResizePLAB) { 102 _g1h->alloc_buffer_stats(InCSetState::Young)->adjust_desired_plab_sz(no_of_gc_workers); 103 _g1h->alloc_buffer_stats(InCSetState::Old)->adjust_desired_plab_sz(no_of_gc_workers); 104 } 105 } 106 107 void G1DefaultAllocator::abandon_gc_alloc_regions() { 108 assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition"); 109 assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition"); 110 _retained_old_gc_alloc_region = NULL; 111 } 112 113 G1ParGCAllocBuffer::G1ParGCAllocBuffer(size_t gclab_word_size) : 114 ParGCAllocBuffer(gclab_word_size), _retired(true) { } 115 116 HeapWord* G1ParGCAllocator::allocate_direct_or_new_plab(InCSetState dest, 117 size_t word_sz, 118 AllocationContext_t context) { 119 size_t gclab_word_size = _g1h->desired_plab_sz(dest); 120 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) { 121 G1ParGCAllocBuffer* alloc_buf = alloc_buffer(dest, context); 122 add_to_alloc_buffer_waste(alloc_buf->words_remaining()); 123 alloc_buf->retire(); 124 125 HeapWord* buf = _g1h->par_allocate_during_gc(dest, gclab_word_size, context); 126 if (buf == NULL) { 127 return NULL; // Let caller handle allocation failure. 128 } 129 // Otherwise. 130 alloc_buf->set_word_size(gclab_word_size); 131 alloc_buf->set_buf(buf); 132 133 HeapWord* const obj = alloc_buf->allocate(word_sz); 134 assert(obj != NULL, "buffer was definitely big enough..."); 135 return obj; 136 } else { 137 return _g1h->par_allocate_during_gc(dest, word_sz, context); 138 } 139 } 140 141 G1DefaultParGCAllocator::G1DefaultParGCAllocator(G1CollectedHeap* g1h) : 142 G1ParGCAllocator(g1h), 143 _surviving_alloc_buffer(g1h->desired_plab_sz(InCSetState::Young)), 144 _tenured_alloc_buffer(g1h->desired_plab_sz(InCSetState::Old)) { 145 for (uint state = 0; state < InCSetState::Num; state++) { 146 _alloc_buffers[state] = NULL; 147 } 148 _alloc_buffers[InCSetState::Young] = &_surviving_alloc_buffer; 149 _alloc_buffers[InCSetState::Old] = &_tenured_alloc_buffer; 150 } 151 152 void G1DefaultParGCAllocator::retire_alloc_buffers() { 153 for (uint state = 0; state < InCSetState::Num; state++) { 154 G1ParGCAllocBuffer* const buf = _alloc_buffers[state]; 155 if (buf != NULL) { 156 add_to_alloc_buffer_waste(buf->words_remaining()); 157 buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state)); 158 } 159 } 160 }