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view src/share/vm/gc_implementation/g1/concurrentG1Refine.hpp @ 6233:d5bc62fcfac7
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author | zgu |
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date | Thu, 19 Jul 2012 09:10:12 -0400 |
parents | d2a62e0f25eb |
children | b9a9ed0f8eeb |
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/* * Copyright (c) 2001, 2011, 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. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP #include "memory/allocation.hpp" #include "memory/cardTableModRefBS.hpp" #include "runtime/thread.hpp" #include "utilities/globalDefinitions.hpp" // Forward decl class ConcurrentG1RefineThread; class G1RemSet; class ConcurrentG1Refine: public CHeapObj<mtGC> { ConcurrentG1RefineThread** _threads; int _n_threads; int _n_worker_threads; /* * The value of the update buffer queue length falls into one of 3 zones: * green, yellow, red. If the value is in [0, green) nothing is * done, the buffers are left unprocessed to enable the caching effect of the * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement * threads are gradually activated. In [yellow, red) all threads are * running. If the length becomes red (max queue length) the mutators start * processing the buffers. * * There are some interesting cases (when G1UseAdaptiveConcRefinement * is turned off): * 1) green = yellow = red = 0. In this case the mutator will process all * buffers. Except for those that are created by the deferred updates * machinery during a collection. * 2) green = 0. Means no caching. Can be a good way to minimize the * amount of time spent updating rsets during a collection. */ int _green_zone; int _yellow_zone; int _red_zone; int _thread_threshold_step; // Reset the threshold step value based of the current zone boundaries. void reset_threshold_step(); // The cache for card refinement. bool _use_cache; bool _def_use_cache; size_t _n_periods; // Used as clearing epoch // An evicting cache of the number of times each card // is accessed. Reduces, but does not eliminate, the amount // of duplicated processing of dirty cards. enum SomePrivateConstants { epoch_bits = 32, card_num_shift = epoch_bits, epoch_mask = AllBits, card_num_mask = AllBits, // The initial cache size is approximately this fraction // of a maximal cache (i.e. the size needed for all cards // in the heap) InitialCacheFraction = 512 }; const static julong card_num_mask_in_place = (julong) card_num_mask << card_num_shift; typedef struct { julong _value; // | card_num | epoch | } CardEpochCacheEntry; julong make_epoch_entry(unsigned int card_num, unsigned int epoch) { assert(0 <= card_num && card_num < _max_cards, "Bounds"); assert(0 <= epoch && epoch <= _n_periods, "must be"); return ((julong) card_num << card_num_shift) | epoch; } unsigned int extract_epoch(julong v) { return (v & epoch_mask); } unsigned int extract_card_num(julong v) { return (v & card_num_mask_in_place) >> card_num_shift; } typedef struct { unsigned char _count; unsigned char _evict_count; } CardCountCacheEntry; CardCountCacheEntry* _card_counts; CardEpochCacheEntry* _card_epochs; // The current number of buckets in the card count cache size_t _n_card_counts; // The number of cards for the entire reserved heap size_t _max_cards; // The max number of buckets for the card counts and epochs caches. // This is the maximum that the counts and epochs will grow to. // It is specified as a fraction or percentage of _max_cards using // G1MaxHotCardCountSizePercent. size_t _max_n_card_counts; // Possible sizes of the cache: odd primes that roughly double in size. // (See jvmtiTagMap.cpp). enum { MAX_CC_CACHE_INDEX = 15 // maximum index into the cache size array. }; static size_t _cc_cache_sizes[MAX_CC_CACHE_INDEX]; // The index in _cc_cache_sizes corresponding to the size of // _card_counts. int _cache_size_index; bool _expand_card_counts; const jbyte* _ct_bot; jbyte** _hot_cache; int _hot_cache_size; int _n_hot; int _hot_cache_idx; int _hot_cache_par_chunk_size; volatile int _hot_cache_par_claimed_idx; // Needed to workaround 6817995 CardTableModRefBS* _ct_bs; G1CollectedHeap* _g1h; // Helper routine for expand_card_count_cache(). // The arrays used to hold the card counts and the epochs must have // a 1:1 correspondence. Hence they are allocated and freed together. // Returns true if the allocations of both the counts and epochs // were successful; false otherwise. bool allocate_card_count_cache(size_t n, CardCountCacheEntry** counts, CardEpochCacheEntry** epochs); // Expands the arrays that hold the card counts and epochs // to the cache size at index. Returns true if the expansion/ // allocation was successful; false otherwise. bool expand_card_count_cache(int index); // hash a given key (index of card_ptr) with the specified size static unsigned int hash(size_t key, size_t size) { return (unsigned int) (key % size); } // hash a given key (index of card_ptr) unsigned int hash(size_t key) { return hash(key, _n_card_counts); } unsigned int ptr_2_card_num(jbyte* card_ptr) { return (unsigned int) (card_ptr - _ct_bot); } jbyte* card_num_2_ptr(unsigned int card_num) { return (jbyte*) (_ct_bot + card_num); } // Returns the count of this card after incrementing it. jbyte* add_card_count(jbyte* card_ptr, int* count, bool* defer); // Returns true if this card is in a young region bool is_young_card(jbyte* card_ptr); public: ConcurrentG1Refine(); ~ConcurrentG1Refine(); void init(); // Accomplish some initialization that has to wait. void stop(); void reinitialize_threads(); // Iterate over the conc refine threads void threads_do(ThreadClosure *tc); // If this is the first entry for the slot, writes into the cache and // returns NULL. If it causes an eviction, returns the evicted pointer. // Otherwise, its a cache hit, and returns NULL. jbyte* cache_insert(jbyte* card_ptr, bool* defer); // Process the cached entries. void clean_up_cache(int worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq); // Set up for parallel processing of the cards in the hot cache void clear_hot_cache_claimed_index() { _hot_cache_par_claimed_idx = 0; } // Discard entries in the hot cache. void clear_hot_cache() { _hot_cache_idx = 0; _n_hot = 0; } bool hot_cache_is_empty() { return _n_hot == 0; } bool use_cache() { return _use_cache; } void set_use_cache(bool b) { if (b) _use_cache = _def_use_cache; else _use_cache = false; } void clear_and_record_card_counts(); static int thread_num(); void print_worker_threads_on(outputStream* st) const; void set_green_zone(int x) { _green_zone = x; } void set_yellow_zone(int x) { _yellow_zone = x; } void set_red_zone(int x) { _red_zone = x; } int green_zone() const { return _green_zone; } int yellow_zone() const { return _yellow_zone; } int red_zone() const { return _red_zone; } int total_thread_num() const { return _n_threads; } int worker_thread_num() const { return _n_worker_threads; } int thread_threshold_step() const { return _thread_threshold_step; } }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTG1REFINE_HPP