Mercurial > hg > graal-jvmci-8
diff src/share/vm/gc_implementation/g1/g1HotCardCache.cpp @ 10246:194f52aa2f23
7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap
Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich.
Reviewed-by: tschatzl, jmasa
author | johnc |
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date | Thu, 09 May 2013 11:16:39 -0700 |
parents | |
children | 8847586c9037 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/src/share/vm/gc_implementation/g1/g1HotCardCache.cpp Thu May 09 11:16:39 2013 -0700 @@ -0,0 +1,148 @@ +/* + * Copyright (c) 2013, 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 "gc_implementation/g1/heapRegion.hpp" +#include "runtime/atomic.hpp" + +G1HotCardCache::G1HotCardCache(G1CollectedHeap *g1h): + _g1h(g1h), _hot_cache(NULL), _use_cache(false), _card_counts(g1h) {} + +void G1HotCardCache::initialize() { + if (default_use_cache()) { + _use_cache = true; + + _hot_cache_size = (1 << G1ConcRSLogCacheSize); + _hot_cache = NEW_C_HEAP_ARRAY(jbyte*, _hot_cache_size, mtGC); + + _n_hot = 0; + _hot_cache_idx = 0; + + // For refining the cards in the hot cache in parallel + int n_workers = (ParallelGCThreads > 0 ? + _g1h->workers()->total_workers() : 1); + _hot_cache_par_chunk_size = MAX2(1, _hot_cache_size / n_workers); + _hot_cache_par_claimed_idx = 0; + + _card_counts.initialize(); + } +} + +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. + jbyte* res = NULL; + MutexLockerEx x(HotCardCache_lock, Mutex::_no_safepoint_check_flag); + if (_n_hot == _hot_cache_size) { + res = _hot_cache[_hot_cache_idx]; + _n_hot--; + } + + // Now _n_hot < _hot_cache_size, and we can insert at _hot_cache_idx. + _hot_cache[_hot_cache_idx] = card_ptr; + _hot_cache_idx++; + + if (_hot_cache_idx == _hot_cache_size) { + // Wrap around + _hot_cache_idx = 0; + } + _n_hot++; + + return res; +} + +void G1HotCardCache::drain(int 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"); + int start_idx; + + while ((start_idx = _hot_cache_par_claimed_idx) < _n_hot) { // read once + int end_idx = start_idx + _hot_cache_par_chunk_size; + + if (start_idx == + Atomic::cmpxchg(end_idx, &_hot_cache_par_claimed_idx, start_idx)) { + // The current worker has successfully claimed the chunk [start_idx..end_idx) + end_idx = MIN2(end_idx, _n_hot); + for (int 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 < (int) (ParallelGCThreads == 0 ? 1 : ParallelGCThreads), + err_msg("incorrect worker id: "INT32_FORMAT, worker_i)); + + into_cset_dcq->enqueue(card_ptr); + } + } + } + } + } + // 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::resize_card_counts(size_t heap_capacity) { + _card_counts.resize(heap_capacity); +} + +void G1HotCardCache::reset_card_counts(HeapRegion* hr) { + _card_counts.clear_region(hr); +} + +void G1HotCardCache::reset_card_counts() { + _card_counts.clear_all(); +}