1 /* 2 * Copyright (c) 2001, 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/serial/genMarkSweep.hpp" 27 #include "gc/serial/tenuredGeneration.inline.hpp" 28 #include "gc/shared/blockOffsetTable.inline.hpp" 29 #include "gc/shared/cardGeneration.inline.hpp" 30 #include "gc/shared/collectorCounters.hpp" 31 #include "gc/shared/gcTimer.hpp" 32 #include "gc/shared/genOopClosures.inline.hpp" 33 #include "gc/shared/generationSpec.hpp" 34 #include "gc/shared/space.hpp" 35 #include "logging/log.hpp" 36 #include "memory/allocation.inline.hpp" 37 #include "oops/oop.inline.hpp" 38 #include "runtime/java.hpp" 39 #include "utilities/macros.hpp" 40 #if INCLUDE_ALL_GCS 41 #include "gc/cms/parOopClosures.hpp" 42 #endif 43 44 TenuredGeneration::TenuredGeneration(ReservedSpace rs, 45 size_t initial_byte_size, 46 CardTableRS* remset) : 47 CardGeneration(rs, initial_byte_size, remset) 48 { 49 HeapWord* bottom = (HeapWord*) _virtual_space.low(); 50 HeapWord* end = (HeapWord*) _virtual_space.high(); 51 _the_space = new TenuredSpace(_bts, MemRegion(bottom, end)); 52 _the_space->reset_saved_mark(); 53 _shrink_factor = 0; 54 _capacity_at_prologue = 0; 55 56 _gc_stats = new GCStats(); 57 58 // initialize performance counters 59 60 const char* gen_name = "old"; 61 GenCollectorPolicy* gcp = GenCollectedHeap::heap()->gen_policy(); 62 // Generation Counters -- generation 1, 1 subspace 63 _gen_counters = new GenerationCounters(gen_name, 1, 1, 64 gcp->min_old_size(), gcp->max_old_size(), &_virtual_space); 65 66 _gc_counters = new CollectorCounters("MSC", 1); 67 68 // Dummy counter 69 new CollectorCounters("dummy", 2); 70 71 _space_counters = new CSpaceCounters(gen_name, 0, 72 _virtual_space.reserved_size(), 73 _the_space, _gen_counters); 74 } 75 76 void TenuredGeneration::gc_prologue(bool full) { 77 _capacity_at_prologue = capacity(); 78 _used_at_prologue = used(); 79 } 80 81 bool TenuredGeneration::should_collect(bool full, 82 size_t size, 83 bool is_tlab) { 84 // This should be one big conditional or (||), but I want to be able to tell 85 // why it returns what it returns (without re-evaluating the conditionals 86 // in case they aren't idempotent), so I'm doing it this way. 87 // DeMorgan says it's okay. 88 if (full) { 89 log_trace(gc)("TenuredGeneration::should_collect: because full"); 90 return true; 91 } 92 if (should_allocate(size, is_tlab)) { 93 log_trace(gc)("TenuredGeneration::should_collect: because should_allocate(" SIZE_FORMAT ")", size); 94 return true; 95 } 96 // If we don't have very much free space. 97 // XXX: 10000 should be a percentage of the capacity!!! 98 if (free() < 10000) { 99 log_trace(gc)("TenuredGeneration::should_collect: because free(): " SIZE_FORMAT, free()); 100 return true; 101 } 102 // If we had to expand to accommodate promotions from the young generation 103 if (_capacity_at_prologue < capacity()) { 104 log_trace(gc)("TenuredGeneration::should_collect: because_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT, 105 _capacity_at_prologue, capacity()); 106 return true; 107 } 108 109 return false; 110 } 111 112 void TenuredGeneration::compute_new_size() { 113 assert_locked_or_safepoint(Heap_lock); 114 115 // Compute some numbers about the state of the heap. 116 const size_t used_after_gc = used(); 117 const size_t capacity_after_gc = capacity(); 118 119 CardGeneration::compute_new_size(); 120 121 assert(used() == used_after_gc && used_after_gc <= capacity(), 122 "used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT 123 " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity()); 124 } 125 126 void TenuredGeneration::update_gc_stats(Generation* current_generation, 127 bool full) { 128 // If the young generation has been collected, gather any statistics 129 // that are of interest at this point. 130 bool current_is_young = GenCollectedHeap::heap()->is_young_gen(current_generation); 131 if (!full && current_is_young) { 132 // Calculate size of data promoted from the young generation 133 // before doing the collection. 134 size_t used_before_gc = used(); 135 136 // If the young gen collection was skipped, then the 137 // number of promoted bytes will be 0 and adding it to the 138 // average will incorrectly lessen the average. It is, however, 139 // also possible that no promotion was needed. 140 if (used_before_gc >= _used_at_prologue) { 141 size_t promoted_in_bytes = used_before_gc - _used_at_prologue; 142 gc_stats()->avg_promoted()->sample(promoted_in_bytes); 143 } 144 } 145 } 146 147 void TenuredGeneration::update_counters() { 148 if (UsePerfData) { 149 _space_counters->update_all(); 150 _gen_counters->update_all(); 151 } 152 } 153 154 bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const { 155 size_t available = max_contiguous_available(); 156 size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average(); 157 bool res = (available >= av_promo) || (available >= max_promotion_in_bytes); 158 159 log_trace(gc)("Tenured: promo attempt is%s safe: available(" SIZE_FORMAT ") %s av_promo(" SIZE_FORMAT "), max_promo(" SIZE_FORMAT ")", 160 res? "":" not", available, res? ">=":"<", av_promo, max_promotion_in_bytes); 161 162 return res; 163 } 164 165 void TenuredGeneration::collect(bool full, 166 bool clear_all_soft_refs, 167 size_t size, 168 bool is_tlab) { 169 GenCollectedHeap* gch = GenCollectedHeap::heap(); 170 171 // Temporarily expand the span of our ref processor, so 172 // refs discovery is over the entire heap, not just this generation 173 ReferenceProcessorSpanMutator 174 x(ref_processor(), gch->reserved_region()); 175 176 STWGCTimer* gc_timer = GenMarkSweep::gc_timer(); 177 gc_timer->register_gc_start(); 178 179 SerialOldTracer* gc_tracer = GenMarkSweep::gc_tracer(); 180 gc_tracer->report_gc_start(gch->gc_cause(), gc_timer->gc_start()); 181 182 gch->pre_full_gc_dump(gc_timer); 183 184 GenMarkSweep::invoke_at_safepoint(ref_processor(), clear_all_soft_refs); 185 186 gch->post_full_gc_dump(gc_timer); 187 188 gc_timer->register_gc_end(); 189 190 gc_tracer->report_gc_end(gc_timer->gc_end(), gc_timer->time_partitions()); 191 } 192 193 HeapWord* 194 TenuredGeneration::expand_and_allocate(size_t word_size, 195 bool is_tlab, 196 bool parallel) { 197 assert(!is_tlab, "TenuredGeneration does not support TLAB allocation"); 198 if (parallel) { 199 MutexLocker x(ParGCRareEvent_lock); 200 HeapWord* result = NULL; 201 size_t byte_size = word_size * HeapWordSize; 202 while (true) { 203 expand(byte_size, _min_heap_delta_bytes); 204 if (GCExpandToAllocateDelayMillis > 0) { 205 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); 206 } 207 result = _the_space->par_allocate(word_size); 208 if ( result != NULL) { 209 return result; 210 } else { 211 // If there's not enough expansion space available, give up. 212 if (_virtual_space.uncommitted_size() < byte_size) { 213 return NULL; 214 } 215 // else try again 216 } 217 } 218 } else { 219 expand(word_size*HeapWordSize, _min_heap_delta_bytes); 220 return _the_space->allocate(word_size); 221 } 222 } 223 224 bool TenuredGeneration::expand(size_t bytes, size_t expand_bytes) { 225 GCMutexLocker x(ExpandHeap_lock); 226 return CardGeneration::expand(bytes, expand_bytes); 227 } 228 229 size_t TenuredGeneration::unsafe_max_alloc_nogc() const { 230 return _the_space->free(); 231 } 232 233 size_t TenuredGeneration::contiguous_available() const { 234 return _the_space->free() + _virtual_space.uncommitted_size(); 235 } 236 237 void TenuredGeneration::assert_correct_size_change_locking() { 238 assert_locked_or_safepoint(ExpandHeap_lock); 239 } 240 241 // Currently nothing to do. 242 void TenuredGeneration::prepare_for_verify() {} 243 244 void TenuredGeneration::object_iterate(ObjectClosure* blk) { 245 _the_space->object_iterate(blk); 246 } 247 248 void TenuredGeneration::save_marks() { 249 _the_space->set_saved_mark(); 250 } 251 252 void TenuredGeneration::reset_saved_marks() { 253 _the_space->reset_saved_mark(); 254 } 255 256 bool TenuredGeneration::no_allocs_since_save_marks() { 257 return _the_space->saved_mark_at_top(); 258 } 259 260 #define TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ 261 \ 262 void TenuredGeneration:: \ 263 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \ 264 blk->set_generation(this); \ 265 _the_space->oop_since_save_marks_iterate##nv_suffix(blk); \ 266 blk->reset_generation(); \ 267 save_marks(); \ 268 } 269 270 ALL_SINCE_SAVE_MARKS_CLOSURES(TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN) 271 272 #undef TenuredGen_SINCE_SAVE_MARKS_ITERATE_DEFN 273 274 void TenuredGeneration::gc_epilogue(bool full) { 275 // update the generation and space performance counters 276 update_counters(); 277 if (ZapUnusedHeapArea) { 278 _the_space->check_mangled_unused_area_complete(); 279 } 280 } 281 282 void TenuredGeneration::record_spaces_top() { 283 assert(ZapUnusedHeapArea, "Not mangling unused space"); 284 _the_space->set_top_for_allocations(); 285 } 286 287 void TenuredGeneration::verify() { 288 _the_space->verify(); 289 } 290 291 void TenuredGeneration::print_on(outputStream* st) const { 292 Generation::print_on(st); 293 st->print(" the"); 294 _the_space->print_on(st); 295 }