1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/memory/tenuredGeneration.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,301 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "gc_implementation/shared/collectorCounters.hpp"
1.30 +#include "gc_implementation/shared/parGCAllocBuffer.hpp"
1.31 +#include "memory/allocation.inline.hpp"
1.32 +#include "memory/blockOffsetTable.inline.hpp"
1.33 +#include "memory/generation.inline.hpp"
1.34 +#include "memory/generationSpec.hpp"
1.35 +#include "memory/space.hpp"
1.36 +#include "memory/tenuredGeneration.hpp"
1.37 +#include "oops/oop.inline.hpp"
1.38 +#include "runtime/java.hpp"
1.39 +#include "utilities/macros.hpp"
1.40 +
1.41 +TenuredGeneration::TenuredGeneration(ReservedSpace rs,
1.42 + size_t initial_byte_size, int level,
1.43 + GenRemSet* remset) :
1.44 + OneContigSpaceCardGeneration(rs, initial_byte_size,
1.45 + level, remset, NULL)
1.46 +{
1.47 + HeapWord* bottom = (HeapWord*) _virtual_space.low();
1.48 + HeapWord* end = (HeapWord*) _virtual_space.high();
1.49 + _the_space = new TenuredSpace(_bts, MemRegion(bottom, end));
1.50 + _the_space->reset_saved_mark();
1.51 + _shrink_factor = 0;
1.52 + _capacity_at_prologue = 0;
1.53 +
1.54 + _gc_stats = new GCStats();
1.55 +
1.56 + // initialize performance counters
1.57 +
1.58 + const char* gen_name = "old";
1.59 +
1.60 + // Generation Counters -- generation 1, 1 subspace
1.61 + _gen_counters = new GenerationCounters(gen_name, 1, 1, &_virtual_space);
1.62 +
1.63 + _gc_counters = new CollectorCounters("MSC", 1);
1.64 +
1.65 + _space_counters = new CSpaceCounters(gen_name, 0,
1.66 + _virtual_space.reserved_size(),
1.67 + _the_space, _gen_counters);
1.68 +#if INCLUDE_ALL_GCS
1.69 + if (UseParNewGC) {
1.70 + typedef ParGCAllocBufferWithBOT* ParGCAllocBufferWithBOTPtr;
1.71 + _alloc_buffers = NEW_C_HEAP_ARRAY(ParGCAllocBufferWithBOTPtr,
1.72 + ParallelGCThreads, mtGC);
1.73 + if (_alloc_buffers == NULL)
1.74 + vm_exit_during_initialization("Could not allocate alloc_buffers");
1.75 + for (uint i = 0; i < ParallelGCThreads; i++) {
1.76 + _alloc_buffers[i] =
1.77 + new ParGCAllocBufferWithBOT(OldPLABSize, _bts);
1.78 + if (_alloc_buffers[i] == NULL)
1.79 + vm_exit_during_initialization("Could not allocate alloc_buffers");
1.80 + }
1.81 + } else {
1.82 + _alloc_buffers = NULL;
1.83 + }
1.84 +#endif // INCLUDE_ALL_GCS
1.85 +}
1.86 +
1.87 +
1.88 +const char* TenuredGeneration::name() const {
1.89 + return "tenured generation";
1.90 +}
1.91 +
1.92 +void TenuredGeneration::gc_prologue(bool full) {
1.93 + _capacity_at_prologue = capacity();
1.94 + _used_at_prologue = used();
1.95 + if (VerifyBeforeGC) {
1.96 + verify_alloc_buffers_clean();
1.97 + }
1.98 +}
1.99 +
1.100 +void TenuredGeneration::gc_epilogue(bool full) {
1.101 + if (VerifyAfterGC) {
1.102 + verify_alloc_buffers_clean();
1.103 + }
1.104 + OneContigSpaceCardGeneration::gc_epilogue(full);
1.105 +}
1.106 +
1.107 +
1.108 +bool TenuredGeneration::should_collect(bool full,
1.109 + size_t size,
1.110 + bool is_tlab) {
1.111 + // This should be one big conditional or (||), but I want to be able to tell
1.112 + // why it returns what it returns (without re-evaluating the conditionals
1.113 + // in case they aren't idempotent), so I'm doing it this way.
1.114 + // DeMorgan says it's okay.
1.115 + bool result = false;
1.116 + if (!result && full) {
1.117 + result = true;
1.118 + if (PrintGC && Verbose) {
1.119 + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because"
1.120 + " full");
1.121 + }
1.122 + }
1.123 + if (!result && should_allocate(size, is_tlab)) {
1.124 + result = true;
1.125 + if (PrintGC && Verbose) {
1.126 + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because"
1.127 + " should_allocate(" SIZE_FORMAT ")",
1.128 + size);
1.129 + }
1.130 + }
1.131 + // If we don't have very much free space.
1.132 + // XXX: 10000 should be a percentage of the capacity!!!
1.133 + if (!result && free() < 10000) {
1.134 + result = true;
1.135 + if (PrintGC && Verbose) {
1.136 + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because"
1.137 + " free(): " SIZE_FORMAT,
1.138 + free());
1.139 + }
1.140 + }
1.141 + // If we had to expand to accomodate promotions from younger generations
1.142 + if (!result && _capacity_at_prologue < capacity()) {
1.143 + result = true;
1.144 + if (PrintGC && Verbose) {
1.145 + gclog_or_tty->print_cr("TenuredGeneration::should_collect: because"
1.146 + "_capacity_at_prologue: " SIZE_FORMAT " < capacity(): " SIZE_FORMAT,
1.147 + _capacity_at_prologue, capacity());
1.148 + }
1.149 + }
1.150 + return result;
1.151 +}
1.152 +
1.153 +void TenuredGeneration::collect(bool full,
1.154 + bool clear_all_soft_refs,
1.155 + size_t size,
1.156 + bool is_tlab) {
1.157 + retire_alloc_buffers_before_full_gc();
1.158 + OneContigSpaceCardGeneration::collect(full, clear_all_soft_refs,
1.159 + size, is_tlab);
1.160 +}
1.161 +
1.162 +void TenuredGeneration::compute_new_size() {
1.163 + assert_locked_or_safepoint(Heap_lock);
1.164 +
1.165 + // Compute some numbers about the state of the heap.
1.166 + const size_t used_after_gc = used();
1.167 + const size_t capacity_after_gc = capacity();
1.168 +
1.169 + CardGeneration::compute_new_size();
1.170 +
1.171 + assert(used() == used_after_gc && used_after_gc <= capacity(),
1.172 + err_msg("used: " SIZE_FORMAT " used_after_gc: " SIZE_FORMAT
1.173 + " capacity: " SIZE_FORMAT, used(), used_after_gc, capacity()));
1.174 +}
1.175 +void TenuredGeneration::update_gc_stats(int current_level,
1.176 + bool full) {
1.177 + // If the next lower level(s) has been collected, gather any statistics
1.178 + // that are of interest at this point.
1.179 + if (!full && (current_level + 1) == level()) {
1.180 + // Calculate size of data promoted from the younger generations
1.181 + // before doing the collection.
1.182 + size_t used_before_gc = used();
1.183 +
1.184 + // If the younger gen collections were skipped, then the
1.185 + // number of promoted bytes will be 0 and adding it to the
1.186 + // average will incorrectly lessen the average. It is, however,
1.187 + // also possible that no promotion was needed.
1.188 + if (used_before_gc >= _used_at_prologue) {
1.189 + size_t promoted_in_bytes = used_before_gc - _used_at_prologue;
1.190 + gc_stats()->avg_promoted()->sample(promoted_in_bytes);
1.191 + }
1.192 + }
1.193 +}
1.194 +
1.195 +void TenuredGeneration::update_counters() {
1.196 + if (UsePerfData) {
1.197 + _space_counters->update_all();
1.198 + _gen_counters->update_all();
1.199 + }
1.200 +}
1.201 +
1.202 +
1.203 +#if INCLUDE_ALL_GCS
1.204 +oop TenuredGeneration::par_promote(int thread_num,
1.205 + oop old, markOop m, size_t word_sz) {
1.206 +
1.207 + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
1.208 + HeapWord* obj_ptr = buf->allocate(word_sz);
1.209 + bool is_lab = true;
1.210 + if (obj_ptr == NULL) {
1.211 +#ifndef PRODUCT
1.212 + if (Universe::heap()->promotion_should_fail()) {
1.213 + return NULL;
1.214 + }
1.215 +#endif // #ifndef PRODUCT
1.216 +
1.217 + // Slow path:
1.218 + if (word_sz * 100 < ParallelGCBufferWastePct * buf->word_sz()) {
1.219 + // Is small enough; abandon this buffer and start a new one.
1.220 + size_t buf_size = buf->word_sz();
1.221 + HeapWord* buf_space =
1.222 + TenuredGeneration::par_allocate(buf_size, false);
1.223 + if (buf_space == NULL) {
1.224 + buf_space = expand_and_allocate(buf_size, false, true /* parallel*/);
1.225 + }
1.226 + if (buf_space != NULL) {
1.227 + buf->retire(false, false);
1.228 + buf->set_buf(buf_space);
1.229 + obj_ptr = buf->allocate(word_sz);
1.230 + assert(obj_ptr != NULL, "Buffer was definitely big enough...");
1.231 + }
1.232 + };
1.233 + // Otherwise, buffer allocation failed; try allocating object
1.234 + // individually.
1.235 + if (obj_ptr == NULL) {
1.236 + obj_ptr = TenuredGeneration::par_allocate(word_sz, false);
1.237 + if (obj_ptr == NULL) {
1.238 + obj_ptr = expand_and_allocate(word_sz, false, true /* parallel */);
1.239 + }
1.240 + }
1.241 + if (obj_ptr == NULL) return NULL;
1.242 + }
1.243 + assert(obj_ptr != NULL, "program logic");
1.244 + Copy::aligned_disjoint_words((HeapWord*)old, obj_ptr, word_sz);
1.245 + oop obj = oop(obj_ptr);
1.246 + // Restore the mark word copied above.
1.247 + obj->set_mark(m);
1.248 + return obj;
1.249 +}
1.250 +
1.251 +void TenuredGeneration::par_promote_alloc_undo(int thread_num,
1.252 + HeapWord* obj,
1.253 + size_t word_sz) {
1.254 + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
1.255 + if (buf->contains(obj)) {
1.256 + guarantee(buf->contains(obj + word_sz - 1),
1.257 + "should contain whole object");
1.258 + buf->undo_allocation(obj, word_sz);
1.259 + } else {
1.260 + CollectedHeap::fill_with_object(obj, word_sz);
1.261 + }
1.262 +}
1.263 +
1.264 +void TenuredGeneration::par_promote_alloc_done(int thread_num) {
1.265 + ParGCAllocBufferWithBOT* buf = _alloc_buffers[thread_num];
1.266 + buf->retire(true, ParallelGCRetainPLAB);
1.267 +}
1.268 +
1.269 +void TenuredGeneration::retire_alloc_buffers_before_full_gc() {
1.270 + if (UseParNewGC) {
1.271 + for (uint i = 0; i < ParallelGCThreads; i++) {
1.272 + _alloc_buffers[i]->retire(true /*end_of_gc*/, false /*retain*/);
1.273 + }
1.274 + }
1.275 +}
1.276 +
1.277 +// Verify that any retained parallel allocation buffers do not
1.278 +// intersect with dirty cards.
1.279 +void TenuredGeneration::verify_alloc_buffers_clean() {
1.280 + if (UseParNewGC) {
1.281 + for (uint i = 0; i < ParallelGCThreads; i++) {
1.282 + _rs->verify_aligned_region_empty(_alloc_buffers[i]->range());
1.283 + }
1.284 + }
1.285 +}
1.286 +
1.287 +#else // INCLUDE_ALL_GCS
1.288 +void TenuredGeneration::retire_alloc_buffers_before_full_gc() {}
1.289 +void TenuredGeneration::verify_alloc_buffers_clean() {}
1.290 +#endif // INCLUDE_ALL_GCS
1.291 +
1.292 +bool TenuredGeneration::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
1.293 + size_t available = max_contiguous_available();
1.294 + size_t av_promo = (size_t)gc_stats()->avg_promoted()->padded_average();
1.295 + bool res = (available >= av_promo) || (available >= max_promotion_in_bytes);
1.296 + if (PrintGC && Verbose) {
1.297 + gclog_or_tty->print_cr(
1.298 + "Tenured: promo attempt is%s safe: available("SIZE_FORMAT") %s av_promo("SIZE_FORMAT"),"
1.299 + "max_promo("SIZE_FORMAT")",
1.300 + res? "":" not", available, res? ">=":"<",
1.301 + av_promo, max_promotion_in_bytes);
1.302 + }
1.303 + return res;
1.304 +}
