johnc@5078: /*
johnc@5078:  * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
johnc@5078:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
johnc@5078:  *
johnc@5078:  * This code is free software; you can redistribute it and/or modify it
johnc@5078:  * under the terms of the GNU General Public License version 2 only, as
johnc@5078:  * published by the Free Software Foundation.
johnc@5078:  *
johnc@5078:  * This code is distributed in the hope that it will be useful, but WITHOUT
johnc@5078:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
johnc@5078:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
johnc@5078:  * version 2 for more details (a copy is included in the LICENSE file that
johnc@5078:  * accompanied this code).
johnc@5078:  *
johnc@5078:  * You should have received a copy of the GNU General Public License version
johnc@5078:  * 2 along with this work; if not, write to the Free Software Foundation,
johnc@5078:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
johnc@5078:  *
johnc@5078:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
johnc@5078:  * or visit www.oracle.com if you need additional information or have any
johnc@5078:  * questions.
johnc@5078:  *
johnc@5078:  */
johnc@5078: 
johnc@5078: #include "precompiled.hpp"
johnc@5078: #include "gc_implementation/g1/dirtyCardQueue.hpp"
johnc@5078: #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
johnc@5078: #include "gc_implementation/g1/g1HotCardCache.hpp"
johnc@5078: #include "gc_implementation/g1/g1RemSet.hpp"
johnc@5078: #include "gc_implementation/g1/heapRegion.hpp"
johnc@5078: #include "runtime/atomic.hpp"
johnc@5078: 
johnc@5078: G1HotCardCache::G1HotCardCache(G1CollectedHeap *g1h):
johnc@5078:   _g1h(g1h), _hot_cache(NULL), _use_cache(false), _card_counts(g1h) {}
johnc@5078: 
johnc@5078: void G1HotCardCache::initialize() {
johnc@5078:   if (default_use_cache()) {
johnc@5078:     _use_cache = true;
johnc@5078: 
johnc@5078:     _hot_cache_size = (1 << G1ConcRSLogCacheSize);
johnc@5078:     _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size, mtGC);
johnc@5078: 
johnc@5078:     _n_hot = 0;
johnc@5078:     _hot_cache_idx = 0;
johnc@5078: 
johnc@5078:     // For refining the cards in the hot cache in parallel
johnc@5078:     int n_workers = (ParallelGCThreads > 0 ?
johnc@5078:                         _g1h->workers()->total_workers() : 1);
johnc@5078:     _hot_cache_par_chunk_size = MAX2(1, _hot_cache_size / n_workers);
johnc@5078:     _hot_cache_par_claimed_idx = 0;
johnc@5078: 
johnc@5078:     _card_counts.initialize();
johnc@5078:   }
johnc@5078: }
johnc@5078: 
johnc@5078: G1HotCardCache::~G1HotCardCache() {
johnc@5078:   if (default_use_cache()) {
johnc@5078:     assert(_hot_cache != NULL, "Logic");
johnc@5078:     FREE_C_HEAP_ARRAY(jbyte*, _hot_cache, mtGC);
johnc@5078:   }
johnc@5078: }
johnc@5078: 
johnc@5078: jbyte* G1HotCardCache::insert(jbyte* card_ptr) {
johnc@5078:   uint count = _card_counts.add_card_count(card_ptr);
johnc@5078:   if (!_card_counts.is_hot(count)) {
johnc@5078:     // The card is not hot so do not store it in the cache;
johnc@5078:     // return it for immediate refining.
johnc@5078:     return card_ptr;
johnc@5078:   }
johnc@5078: 
johnc@5078:   // Otherwise, the card is hot.
johnc@5078:   jbyte* res = NULL;
johnc@5078:   MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag);
johnc@5078:   if (_n_hot == _hot_cache_size) {
johnc@5078:     res = _hot_cache[_hot_cache_idx];
johnc@5078:     _n_hot--;
johnc@5078:   }
johnc@5078: 
johnc@5078:   // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx.
johnc@5078:   _hot_cache[_hot_cache_idx] = card_ptr;
johnc@5078:   _hot_cache_idx++;
johnc@5078: 
johnc@5078:   if (_hot_cache_idx == _hot_cache_size) {
johnc@5078:     // Wrap around
johnc@5078:     _hot_cache_idx = 0;
johnc@5078:   }
johnc@5078:   _n_hot++;
johnc@5078: 
johnc@5078:   return res;
johnc@5078: }
johnc@5078: 
johnc@5078: void G1HotCardCache::drain(int worker_i,
johnc@5078:                            G1RemSet* g1rs,
johnc@5078:                            DirtyCardQueue* into_cset_dcq) {
johnc@5078:   if (!default_use_cache()) {
johnc@5078:     assert(_hot_cache == NULL, "Logic");
johnc@5078:     return;
johnc@5078:   }
johnc@5078: 
johnc@5078:   assert(_hot_cache != NULL, "Logic");
johnc@5078:   assert(!use_cache(), "cache should be disabled");
johnc@5078:   int start_idx;
johnc@5078: 
johnc@5078:   while ((start_idx = _hot_cache_par_claimed_idx) < _n_hot) { // read once
johnc@5078:     int end_idx = start_idx + _hot_cache_par_chunk_size;
johnc@5078: 
johnc@5078:     if (start_idx ==
johnc@5078:         Atomic::cmpxchg(end_idx, &_hot_cache_par_claimed_idx, start_idx)) {
johnc@5078:       // The current worker has successfully claimed the chunk [start_idx..end_idx)
johnc@5078:       end_idx = MIN2(end_idx, _n_hot);
johnc@5078:       for (int i = start_idx; i < end_idx; i++) {
johnc@5078:         jbyte* card_ptr = _hot_cache[i];
johnc@5078:         if (card_ptr != NULL) {
johnc@5078:           if (g1rs->refine_card(card_ptr, worker_i, true)) {
johnc@5078:             // The part of the heap spanned by the card contains references
johnc@5078:             // that point into the current collection set.
johnc@5078:             // We need to record the card pointer in the DirtyCardQueueSet
johnc@5078:             // that we use for such cards.
johnc@5078:             //
johnc@5078:             // The only time we care about recording cards that contain
johnc@5078:             // references that point into the collection set is during
johnc@5078:             // RSet updating while within an evacuation pause.
johnc@5078:             // In this case worker_i should be the id of a GC worker thread
johnc@5078:             assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");
johnc@5078:             assert(worker_i < (int) (ParallelGCThreads == 0 ? 1 : ParallelGCThreads),
johnc@5078:                    err_msg("incorrect worker id: "INT32_FORMAT, worker_i));
johnc@5078: 
johnc@5078:             into_cset_dcq->enqueue(card_ptr);
johnc@5078:           }
johnc@5078:         }
johnc@5078:       }
johnc@5078:     }
johnc@5078:   }
johnc@5078:   // The existing entries in the hot card cache, which were just refined
johnc@5078:   // above, are discarded prior to re-enabling the cache near the end of the GC.
johnc@5078: }
johnc@5078: 
johnc@5078: void G1HotCardCache::resize_card_counts(size_t heap_capacity) {
johnc@5078:   _card_counts.resize(heap_capacity);
johnc@5078: }
johnc@5078: 
johnc@5078: void G1HotCardCache::reset_card_counts(HeapRegion* hr) {
johnc@5078:   _card_counts.clear_region(hr);
johnc@5078: }
johnc@5078: 
johnc@5078: void G1HotCardCache::reset_card_counts() {
johnc@5078:   _card_counts.clear_all();
johnc@5078: }