1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/g1HotCardCache.cpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,148 @@
1.4 +/*
1.5 + * Copyright (c) 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/g1/dirtyCardQueue.hpp"
1.30 +#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
1.31 +#include "gc_implementation/g1/g1HotCardCache.hpp"
1.32 +#include "gc_implementation/g1/g1RemSet.hpp"
1.33 +#include "gc_implementation/g1/heapRegion.hpp"
1.34 +#include "runtime/atomic.hpp"
1.35 +
1.36 +G1HotCardCache::G1HotCardCache(G1CollectedHeap *g1h):
1.37 + _g1h(g1h), _hot_cache(NULL), _use_cache(false), _card_counts(g1h) {}
1.38 +
1.39 +void G1HotCardCache::initialize() {
1.40 + if (default_use_cache()) {
1.41 + _use_cache = true;
1.42 +
1.43 + _hot_cache_size = (1 << G1ConcRSLogCacheSize);
1.44 + _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size, mtGC);
1.45 +
1.46 + _n_hot = 0;
1.47 + _hot_cache_idx = 0;
1.48 +
1.49 + // For refining the cards in the hot cache in parallel
1.50 + uint n_workers = (ParallelGCThreads > 0 ?
1.51 + _g1h->workers()->total_workers() : 1);
1.52 + _hot_cache_par_chunk_size = MAX2(1, _hot_cache_size / (int)n_workers);
1.53 + _hot_cache_par_claimed_idx = 0;
1.54 +
1.55 + _card_counts.initialize();
1.56 + }
1.57 +}
1.58 +
1.59 +G1HotCardCache::~G1HotCardCache() {
1.60 + if (default_use_cache()) {
1.61 + assert(_hot_cache != NULL, "Logic");
1.62 + FREE_C_HEAP_ARRAY(jbyte*, _hot_cache, mtGC);
1.63 + }
1.64 +}
1.65 +
1.66 +jbyte* G1HotCardCache::insert(jbyte* card_ptr) {
1.67 + uint count = _card_counts.add_card_count(card_ptr);
1.68 + if (!_card_counts.is_hot(count)) {
1.69 + // The card is not hot so do not store it in the cache;
1.70 + // return it for immediate refining.
1.71 + return card_ptr;
1.72 + }
1.73 +
1.74 + // Otherwise, the card is hot.
1.75 + jbyte* res = NULL;
1.76 + MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag);
1.77 + if (_n_hot == _hot_cache_size) {
1.78 + res = _hot_cache[_hot_cache_idx];
1.79 + _n_hot--;
1.80 + }
1.81 +
1.82 + // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx.
1.83 + _hot_cache[_hot_cache_idx] = card_ptr;
1.84 + _hot_cache_idx++;
1.85 +
1.86 + if (_hot_cache_idx == _hot_cache_size) {
1.87 + // Wrap around
1.88 + _hot_cache_idx = 0;
1.89 + }
1.90 + _n_hot++;
1.91 +
1.92 + return res;
1.93 +}
1.94 +
1.95 +void G1HotCardCache::drain(uint worker_i,
1.96 + G1RemSet* g1rs,
1.97 + DirtyCardQueue* into_cset_dcq) {
1.98 + if (!default_use_cache()) {
1.99 + assert(_hot_cache == NULL, "Logic");
1.100 + return;
1.101 + }
1.102 +
1.103 + assert(_hot_cache != NULL, "Logic");
1.104 + assert(!use_cache(), "cache should be disabled");
1.105 + int start_idx;
1.106 +
1.107 + while ((start_idx = _hot_cache_par_claimed_idx) < _n_hot) { // read once
1.108 + int end_idx = start_idx + _hot_cache_par_chunk_size;
1.109 +
1.110 + if (start_idx ==
1.111 + Atomic::cmpxchg(end_idx, &_hot_cache_par_claimed_idx, start_idx)) {
1.112 + // The current worker has successfully claimed the chunk [start_idx..end_idx)
1.113 + end_idx = MIN2(end_idx, _n_hot);
1.114 + for (int i = start_idx; i < end_idx; i++) {
1.115 + jbyte* card_ptr = _hot_cache[i];
1.116 + if (card_ptr != NULL) {
1.117 + if (g1rs->refine_card(card_ptr, worker_i, true)) {
1.118 + // The part of the heap spanned by the card contains references
1.119 + // that point into the current collection set.
1.120 + // We need to record the card pointer in the DirtyCardQueueSet
1.121 + // that we use for such cards.
1.122 + //
1.123 + // The only time we care about recording cards that contain
1.124 + // references that point into the collection set is during
1.125 + // RSet updating while within an evacuation pause.
1.126 + // In this case worker_i should be the id of a GC worker thread
1.127 + assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");
1.128 + assert(worker_i < (ParallelGCThreads == 0 ? 1 : ParallelGCThreads),
1.129 + err_msg("incorrect worker id: "UINT32_FORMAT, worker_i));
1.130 +
1.131 + into_cset_dcq->enqueue(card_ptr);
1.132 + }
1.133 + }
1.134 + }
1.135 + }
1.136 + }
1.137 + // The existing entries in the hot card cache, which were just refined
1.138 + // above, are discarded prior to re-enabling the cache near the end of the GC.
1.139 +}
1.140 +
1.141 +void G1HotCardCache::resize_card_counts(size_t heap_capacity) {
1.142 + _card_counts.resize(heap_capacity);
1.143 +}
1.144 +
1.145 +void G1HotCardCache::reset_card_counts(HeapRegion* hr) {
1.146 + _card_counts.clear_region(hr);
1.147 +}
1.148 +
1.149 +void G1HotCardCache::reset_card_counts() {
1.150 + _card_counts.clear_all();
1.151 +}
