| /* |
| * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "gc_implementation/g1/dirtyCardQueue.hpp" |
| #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" |
| #include "gc_implementation/g1/g1HotCardCache.hpp" |
| #include "gc_implementation/g1/g1RemSet.hpp" |
| #include "runtime/atomic.hpp" |
| |
| G1HotCardCache::G1HotCardCache(G1CollectedHeap *g1h): |
| _g1h(g1h), _hot_cache(NULL), _use_cache(false), _card_counts(g1h) {} |
| |
| void G1HotCardCache::initialize(G1RegionToSpaceMapper* card_counts_storage) { |
| if (default_use_cache()) { |
| _use_cache = true; |
| |
| _hot_cache_size = (size_t)1 << G1ConcRSLogCacheSize; |
| _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size, mtGC); |
| |
| reset_hot_cache_internal(); |
| |
| // For refining the cards in the hot cache in parallel |
| _hot_cache_par_chunk_size = (int)(ParallelGCThreads > 0 ? ClaimChunkSize : _hot_cache_size); |
| _hot_cache_par_claimed_idx = 0; |
| |
| _card_counts.initialize(card_counts_storage); |
| } |
| } |
| |
| G1HotCardCache::~G1HotCardCache() { |
| if (default_use_cache()) { |
| assert(_hot_cache != NULL, "Logic"); |
| FREE_C_HEAP_ARRAY(jbyte*, _hot_cache, mtGC); |
| } |
| } |
| |
| jbyte* G1HotCardCache::insert(jbyte* card_ptr) { |
| uint count = _card_counts.add_card_count(card_ptr); |
| if (!_card_counts.is_hot(count)) { |
| // The card is not hot so do not store it in the cache; |
| // return it for immediate refining. |
| return card_ptr; |
| } |
| // Otherwise, the card is hot. |
| size_t index = Atomic::add_ptr((intptr_t)1, (volatile intptr_t*)&_hot_cache_idx) - 1; |
| size_t masked_index = index & (_hot_cache_size - 1); |
| jbyte* current_ptr = _hot_cache[masked_index]; |
| |
| // Try to store the new card pointer into the cache. Compare-and-swap to guard |
| // against the unlikely event of a race resulting in another card pointer to |
| // have already been written to the cache. In this case we will return |
| // card_ptr in favor of the other option, which would be starting over. This |
| // should be OK since card_ptr will likely be the older card already when/if |
| // this ever happens. |
| jbyte* previous_ptr = (jbyte*)Atomic::cmpxchg_ptr(card_ptr, |
| &_hot_cache[masked_index], |
| current_ptr); |
| return (previous_ptr == current_ptr) ? previous_ptr : card_ptr; |
| } |
| |
| void G1HotCardCache::drain(uint worker_i, |
| G1RemSet* g1rs, |
| DirtyCardQueue* into_cset_dcq) { |
| if (!default_use_cache()) { |
| assert(_hot_cache == NULL, "Logic"); |
| return; |
| } |
| |
| assert(_hot_cache != NULL, "Logic"); |
| assert(!use_cache(), "cache should be disabled"); |
| while (_hot_cache_par_claimed_idx < _hot_cache_size) { |
| size_t end_idx = Atomic::add_ptr((intptr_t)_hot_cache_par_chunk_size, |
| (volatile intptr_t*)&_hot_cache_par_claimed_idx); |
| size_t start_idx = end_idx - _hot_cache_par_chunk_size; |
| // The current worker has successfully claimed the chunk [start_idx..end_idx) |
| end_idx = MIN2(end_idx, _hot_cache_size); |
| for (size_t i = start_idx; i < end_idx; i++) { |
| jbyte* card_ptr = _hot_cache[i]; |
| if (card_ptr != NULL) { |
| if (g1rs->refine_card(card_ptr, worker_i, true)) { |
| // The part of the heap spanned by the card contains references |
| // that point into the current collection set. |
| // We need to record the card pointer in the DirtyCardQueueSet |
| // that we use for such cards. |
| // |
| // The only time we care about recording cards that contain |
| // references that point into the collection set is during |
| // RSet updating while within an evacuation pause. |
| // In this case worker_i should be the id of a GC worker thread |
| assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint"); |
| assert(worker_i < ParallelGCThreads, |
| err_msg("incorrect worker id: %u", worker_i)); |
| |
| into_cset_dcq->enqueue(card_ptr); |
| } |
| } else { |
| break; |
| } |
| } |
| } |
| |
| // The existing entries in the hot card cache, which were just refined |
| // above, are discarded prior to re-enabling the cache near the end of the GC. |
| } |
| |
| void G1HotCardCache::reset_card_counts(HeapRegion* hr) { |
| _card_counts.clear_region(hr); |
| } |
| |
| void G1HotCardCache::reset_card_counts() { |
| _card_counts.clear_all(); |
| } |