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comparison src/share/vm/gc_implementation/g1/g1Allocator.cpp @ 20404:227a9e5e4b4a

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8057536: Refactor G1 to allow context specific allocations Summary: Splitting out a g1 allocator class to simply specialized allocators which can associate each allocation with a given context. Reviewed-by: mgerdin, brutisso
author sjohanss
date Fri, 05 Sep 2014 09:49:19 +0200
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20403:8ec8971f511a 20404:227a9e5e4b4a
1 /*
2 * Copyright (c) 2014, 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->isHumongous()) {
62 retained_region->record_top_and_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
98 if (ResizePLAB) {
99 _g1h->_survivor_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
100 _g1h->_old_plab_stats.adjust_desired_plab_sz(no_of_gc_workers);
101 }
102 }
103
104 void G1DefaultAllocator::abandon_gc_alloc_regions() {
105 assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
106 assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
107 _retained_old_gc_alloc_region = NULL;
108 }
109
110 G1ParGCAllocBuffer::G1ParGCAllocBuffer(size_t gclab_word_size) :
111 ParGCAllocBuffer(gclab_word_size), _retired(true) { }
112
113 HeapWord* G1ParGCAllocator::allocate_slow(GCAllocPurpose purpose, size_t word_sz, AllocationContext_t context) {
114 HeapWord* obj = NULL;
115 size_t gclab_word_size = _g1h->desired_plab_sz(purpose);
116 if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
117 G1ParGCAllocBuffer* alloc_buf = alloc_buffer(purpose, context);
118 add_to_alloc_buffer_waste(alloc_buf->words_remaining());
119 alloc_buf->retire(false /* end_of_gc */, false /* retain */);
120
121 HeapWord* buf = _g1h->par_allocate_during_gc(purpose, gclab_word_size, context);
122 if (buf == NULL) {
123 return NULL; // Let caller handle allocation failure.
124 }
125 // Otherwise.
126 alloc_buf->set_word_size(gclab_word_size);
127 alloc_buf->set_buf(buf);
128
129 obj = alloc_buf->allocate(word_sz);
130 assert(obj != NULL, "buffer was definitely big enough...");
131 } else {
132 obj = _g1h->par_allocate_during_gc(purpose, word_sz, context);
133 }
134 return obj;
135 }
136
137 G1DefaultParGCAllocator::G1DefaultParGCAllocator(G1CollectedHeap* g1h) :
138 G1ParGCAllocator(g1h),
139 _surviving_alloc_buffer(g1h->desired_plab_sz(GCAllocForSurvived)),
140 _tenured_alloc_buffer(g1h->desired_plab_sz(GCAllocForTenured)) {
141
142 _alloc_buffers[GCAllocForSurvived] = &_surviving_alloc_buffer;
143 _alloc_buffers[GCAllocForTenured] = &_tenured_alloc_buffer;
144
145 }
146
147 void G1DefaultParGCAllocator::retire_alloc_buffers() {
148 for (int ap = 0; ap < GCAllocPurposeCount; ++ap) {
149 size_t waste = _alloc_buffers[ap]->words_remaining();
150 add_to_alloc_buffer_waste(waste);
151 _alloc_buffers[ap]->flush_stats_and_retire(_g1h->stats_for_purpose((GCAllocPurpose)ap),
152 true /* end_of_gc */,
153 false /* retain */);
154 }
155 }