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